Oklahoma City bomber Timothy McVeigh (search) walked into a hair salon one day before the blast with a man who resembled an FBI sketch of a suspect, witnesses said Monday at bombing conspirator Terry Nichols' (search) trial.

McVeigh's contacts, including an enigmatic, dark-skinned man known as John Doe No. 2, are the key to Nichols' defense. His attorneys claim others helped McVeigh plan and execute the 1995 bombing and that Nichols was set up to take the blame.

Early in the investigation, the FBI released the sketch of John Doe No. 2, who was believed to have helped McVeigh rent the truck that blew up outside the Alfred P. Murrah Federal Building (search).

The man eventually was identified as an Army private who had been in the rental shop the day after McVeigh, and was cleared of involvement in the blast that killed 168 people.

But Nichols contends that John Doe No. 2 was real and that his existence sheds doubt on Nichols' purported role in the bombing.

Kathy Henderson, who worked in a hair salon in Junction City, Kan., testified Monday that the sketches of McVeigh and John Doe No. 2 look "almost exactly" like the men who came into the salon together a day before the bombing.

Tonia Rumbaugh, another employee, said the unidentified man appeared to be Hispanic, with thick, dark hair that was tinged with gray.

McVeigh stood at the door while the other man asked for a haircut, but there were no open appointments, Rumbaugh said.

Nichols, 49, is serving a life prison sentence on involuntary manslaughter and conspiracy counts in the deaths of eight federal law enforcement officers in the bombing.

In Oklahoma, he faces 161 counts of first-degree murder for the deaths of the other 160 victims and one victim's fetus.

McVeigh was convicted on federal murder charges and executed in 2001.