On 27 October 1961, Mittel received a call from Conklin, who requested that Mittel stand as his best-man in Conklin's marriage to Marjorie Lowe. Mittel refused, insisting that such a marriage would ruin Conklin's career and Mittel's plans for his political future. Conklin was adamant, but Mittel's worry was short-lived when Lowe turned up dead in an alleyway in Hollywood the next morning.
Mittel later served as campaign manager for Conklin's run for District Attorney in 1962. In November of 1962, Mittel was listed as the Vice President of McCage Inc., through which monthly payments of $1,000 were routed to LAPD detective Claude Eno.
By 1968, he was preparing to launch a campaign for Conklin's run at the office of the Attorney General, and advised Conklin to marry in order to squash rumors that he was homosexual. At that time, Mittel made reference to having "taken care of" Lowe, and Conklin assumed that Mittel had been involved in Marjorie's death. The two parted ways, and did not speak again.
By early 1994, Mittel was hired by Robert Shepherd to organize funds for an exploratory campaign for a Senate run. In April, he held a fundraising party which LAPD detective Harry Bosch managed to attend, and met Bosch (under the alias of "Harvey Pounds"). Later in the evening, he received a newspaper clipping from 1962 announcing the death of one of Conklin's campaign workers with a note inquiring after Fox's credentials, and found the name of "Marjorie Lowe" in the event's guestbook.
Soon after, Mittel instructed Vaughn to find out what "Pounds" knew and who he had told, not realizing that Pounds was not the man he'd met. Mittel later instructed Vaughn to set up surveillance on Conklin, and Vaughn captured Bosch in the process, delivering him to Mittel's estate. Bosch managed to escape his captors, however, and after a fight and chase, Mittel fell over the balcony of his house and down a 150-foot bluff into a neighbor's hot tub, killing him.