6.  The applicant was born in 1961 and lives in Frankfurt am Main. 7.  On 30 October 2013 the Frankfurt am Main District Court issued an arrest warrant against the applicant as there was a strong suspicion that he had aided the commission of crimes, worth several million euros, of aggravated fraudulent conversion, corruption, corruption in commercial practice and aggravated tax evasion through an elaborate system of bribes and fictitious invoices in connection with international business undertakings by a company. The arrest warrant was based on the risk of his absconding owing to the possible heavy sentence for the offences in question. He was also married to the co-accused, who, like him, was a national of the Russian Federation, and he did not have a legal residence or other significant ties to Germany. There was also a risk of collusion. On the same day, he was arrested and the District Court ordered his detention on remand. On 11 September 2014 the District Court included additional charges in the arrest warrant. 8.  On 19 December 2014 the Frankfurt am Main prosecution authorities brought criminal proceedings against the applicant, charging him with eight counts of aiding aggravated fraudulent conversion, one count of aiding aggravated corruption and fourteen counts of aiding aggravated tax evasion. On 26 January 2015 the Darmstadt Regional Court sent the translation of the 280-page indictment to the applicant. On 6 March 2015 he responded to the indictment and asked the court not to open the main proceedings. On 18 March 2015 the prosecution authorities asked the Regional Court to amend the proceedings against the applicant, based on the results of the investigation obtained after the criminal proceedings had been brought. 9.  On 6 May 2015 the Regional Court decided to open the main proceedings, which commenced on 8 June 2015. On 14 July 2016 the Regional Court convicted the applicant on five counts each of aiding fraudulent conversion and tax evasion and sentenced him to four years and six months’ imprisonment. The conviction has not yet become final, with appeals lodged by both the applicant and the prosecution authorities still pending at the time the Court examined the application. 10.  On 26 October 2016 the Frankfurt am Main District Court decided to set aside the arrest warrant of 30 October 2013, which since the outset had been the basis for the applicant’s continuous detention on remand. 11.  From 15 January 2014 onwards the applicant challenged the lawfulness of his remand detention before the Frankfurt am Main District Court and the Frankfurt am Main Regional Court without success. Following a request by the prosecution authorities, the Frankfurt am Main Court of Appeal on 28 July 2014 ordered the prolongation of the applicant’s remand detention. It also ordered that the case file be re-submitted to it by 28 October 2014 at the latest for the next periodic review. Until that time, it transferred the competency for further reviews to the court having jurisdiction according to the general provisions (see paragraphs 21 and 22 below). It considered that there was a risk that the applicant might abscond and that continued detention on remand was not disproportionate in light of the sentence which he risked incurring if found guilty. On 5 September 2014 the applicant lodged a constitutional complaint with the Federal Constitutional Court against that decision. The court refused to accept it for adjudication, without providing reasons (no. 2 BvR 2050/14), a decision which was served on the applicant on 6 October 2014. 12.  Subsequently, the applicant initiated another set of review proceedings before the District Court and lodged a complaint of bias against the competent judge. The complaint was eventually rejected in accordance with the proceedings prescribed by law, as were the remedies pursued by the applicant. On 8 December 2014 the Frankfurt am Main District Court dismissed an application from the applicant to set aside the detention order as it had become devoid of purpose (prozessual überholt) because the Frankfurt am Main Court of Appeal had been seized with a review of the applicant’s detention under Articles 121 et seq. of the Code of Criminal Procedure. 13.  On 24 October 2014 the prosecution authorities submitted a statement and the case file to the Frankfurt am Main Court of Appeal, requesting the extension of the applicant’s detention on remand in accordance with Articles 121 et seq. of the Code of Criminal Procedure. 14.  On 7 November 2014 the applicant requested that the detention order be set aside. He also requested that the Court of Appeal decide on his objection and an appeal to be heard, lodged on 25 August 2014 against the Court of Appeal’s decision of 28 July 2014, prior to the expiry of the time‑limit given to him to respond to the prosecution authorities’ submission. On 10 November 2014 the Court of Appeal dismissed the objection and the appeal to be heard. 15.  On 19 November 2014 the names of the judges called to decide on the continuation of the applicant’s detention were disclosed to the applicant, following his request of the same day. On 25 November 2014 the applicant lodged a complaint of bias against two of the three judges concerned, arguing that they had repeatedly contacted the wrong authorities – either the Frankfurt am Main District Court or Regional Court, rather than the prosecution authorities – to request the case file and had taken two and half months to decide on his objection and appeal to be heard. That had amounted to an arbitrary handling of his case and the judges involved could not decide on the continuation of his detention with the necessary impartiality. The judges gave their statements on 27 November 2014 and 1 December 2014. The applicant then requested additional statements from them, which was not deemed to be necessary by the Court of Appeal on 11 December 2014. Four days later the applicant lodged another complaint about bias, arguing that their statements in response to his first such complaint could not restore his confidence in their impartiality. The judges concerned again gave statements and the applicant’s counsel was given the opportunity to respond. On 30 December 2014 the Court of Appeal rejected the applicant’s first complaint of bias as ill-founded, finding that there were no indications that the judges concerned were partial, even assuming that they had made a procedural mistake in connection with requesting the case file, leading to a delay in deciding on his objection and appeal to be heard. On 8 January 2015 the applicant lodged an objection against that decision. On 22 January 2015 the Court of Appeal rejected the applicant’s second complaint of bias as ill-founded, also addressing his objection in its decision. 16.  On 26 January 2015 the Court of Appeal asked the Frankfurt am Main Regional Court about the current state of the criminal proceedings and what developments there had been. The Court of Appeal was informed by the prosecution authorities that the criminal proceedings had been brought before the Darmstadt Regional Court, rather than the Frankfurt am Main Regional Court, so the Court of Appeal made a similar enquiry to the court in question on 3 February 2015. 17.  On 10 March 2015 the applicant’s lawyer sent to the Court of Appeal two comprehensive submissions which he had made in the main proceedings before the Regional Court and asked the appeal court to take them into account when deciding on the continuation of the applicant’s remand detention. 18.  On 27 March 2015 and on 10 April 2015 the applicant lodged two applications with the Court of Appeal, asking it to take a decision in the pending review proceedings without delay. 19.  On 21 April 2015 the applicant lodged another constitutional complaint with the Federal Constitutional Court, alleging that the absence of a decision by the Court of Appeal in the pending detention review proceedings had violated his right to liberty and security. On 27 April 2015 the Federal Constitutional Court refused to accept the complaint for adjudication without providing reasons (no. 2 BvR 726/15). 20.  On 15 May 2015 the applicant was served with a decision by the Frankfurt am Main Court of Appeal, taken on 15 April 2015 and issued on 13 May 2015, ordering the continuation of his detention on remand. It found that the risk of his absconding continued to exist. It further considered that in the light of, inter alia, the amount of evidence to be examined, the requests for legal assistance sent to several countries, and the scope and complexity of the case, there was no indication of undue delay in the conduct of the criminal proceedings, with the trial being scheduled to commence in June 2015. The applicant’s continued detention on remand was, therefore, proportionate. The court did not address the duration of the review proceedings nor provide any reasons for it.