Complex sentence: To support this contention, they produced several witnesses to testify to the premeditation of Gacy's actions and the efforts he went to in order to escape detection, plus doctors who refuted the defense doctors' claims of multiple personality and insanity.
Split into simpler sentences: To support this contention, they produced several witnesses to testify to the premeditation of Gacy's actions and the efforts he went to in order to escape detection. Those doctors refuted the defense doctors' claims of multiple personality and insanity.