On 1 March 1849, Brown was charged with the murder of "unknown aboriginal natives". In late March or early April he appeared before a local magistrate in the district, Captain G. V. Butler, who committed him for trial. In May, Butler wrote a letter to Charles Hervey Bagot, a member of the South Australian Legislative Council, in which he listed the victims as one "old man blind and infirm", three female adults, two teenage girls (aged 15 and 12 years), and three female children (aged two years, 18 months, and a baby). Butler added that there was "little question of the butchery or the butcher".Brown's trial came before the Supreme Court in Adelaide on 11 June 1849. The presiding judge considered that the evidence presented was insufficient, and gave the prosecution another week to investigate. The weakness of the case was directly related to the provisions of the Aboriginal Witnesses Act of 1848 regarding testimony given by Aboriginal witnesses. It was generally believed that Aboriginal people could not understand the oath, but the Act allowed unsworn testimony to be offered by Aboriginal witnesses, with two significant limitations. The court could determine the weight and credibility to be given to Aboriginal testimony, but even more telling was the restriction that when the punishment for a crime was death or transportation, the evidence of an "uncivilised person or persons" was considered insufficient unless corroborated by other evidence. A week later, the judge remained unconvinced about the strength of the prosecution, but given "great suspicion rested on the case", he gave the prosecution a further extension of time, and released Brown on bail of ₤500.In July 1849, the South Australian Advocate General produced a summary of the investigation to date. Several difficulties were detailed, including the fact that Parker denied any knowledge of the crime, as did others who were believed to have heard the incident, discussed in Brown's presence. Brown's co-accused, Eastwood, alias "Yorkie", had fled when the investigation began and had apparently left the colony aboard a whaling ship off Kangaroo Island. An important witness named Joice had gone to the neighbouring Port Phillip District of the colony of New South Wales, and Leandermin himself, who it appears was being detained at Guichen Bay, absconded and had allegedly been "made away with". The remaining witnesses were those that knew Brown, and apparently would not give evidence against him. Despite the extremely difficult task faced by the prosecution under these circumstances, the Advocate General ordered that investigations continue and issued warrants for the arrest of those that had fled South Australia. Brown appeared at the Supreme Court yet again on 10 and 28 September, but the judge again refused to hear the case without further evidence. By the November sittings of the court, Brown's case had been removed from the listings, and this was the end of the matter as far as the formal investigation was concerned. Effectively, settler solidarity and the law of evidence ensured that Brown was never tried for the murders, despite the fact that those involved in the investigation had no doubt of his guilt. Possibly in response to Brown's case, the Aboriginal Witnesses Act of 1848 was amended in July 1849 to allow a person to be convicted on the sole testimony of an Aboriginal person.

Question: What was the alias of the man co-accused with the person who was charged with the murder of "unknown aboriginal natives"?
Answer: Yorkie