The serial stabber was blamed for as many as 20 attacks at one point, but police determined two of the reported assaults were not likely linked to the serial stabber.
Most of the stabbing victims were black men, but Leyton declined to say the attacks were racially motivated.
"We don't have a motive yet but, as you know, many times the motive doesn't appear until later in the investigation," Leyton said. "Jury instructions don't require us necessarily to have a motive."
Leyton added that a police hotline on the case received more than 500 tips, including the one that sent police looking for Abuelazam.
Abuelazam, who was born in Israel and is of Arab descent, was living in the U.S. legally and has been linked to cities across the country.
Police believe he came to Michigan in May, just days before the attacks began.
"He was a good guy. He was a friendly guy. He was a nice guy," Abuelazam's one-time boss, Abdullah Farah, said today. "He said he was leaving to see some relatives and he never came back."
Investigators believe Abuelazam had an uncle in the Flint, Mich., area as well as a sister in Virginia, Leyton said. He had lived in Leesburg, where he worked at a mental health clinic before traveling to Michigan.
Wendy Brooks told ABC News that she worked with Abuelazam at the Piedmont Behavioral Health Center in Leesburg for several years until 2002 when they both left the facility. She said it was a very stressful job where they frequently had to subdue mentally unstable and violent teenagers, and he was a "gentle giant" whose behavior was marked by patience and restraint.
"He seemed to always treat the kids nicely, followed the rules," Brooks said. "From what I saw, he was never too aggressive. ... I think he was smart. He wasn't quick to react."
At times, she would even seek out Abuelazam "to just kind of talk about a situation. He would sit there and take the time to do it."
Brooks was particularly surprised to find that most of his alleged victims were black.
"It's crazy. I never would've imagined anything like that. I'm a young black female," she said, adding that she gave him a ride home once.
Prior to the attacks, Auelazam had several run-ins with the law including several traffic violations, a check fraud charge and unlawful possession of a weapon. In 2008 he was arrested and held for obstruction of justice. He spent at least one month in jail for a fraud conviction in California.
Abuelazam's ex-wife, who lives in Texas, told The Detroit News she, too, was shocked by the arrest, but hadn't spoken to her ex-husband for a while.
Though the attacks took place from late May through early August, Leyton said law enforcement acted quickly.
"The first two crimes were homicides. The first one was in May and then about a month later was the second one. For those first two, we had absolutely no statement, no suspect, no evidence, no witness. So we had nothing right there," he said. "When we began to see the pattern emerge in late July, that's when everybody said 'This is what we have.'"
Leyton said if Abuelazam waives extradition he could be returned to Michigan as soon as Friday, but could also face charges in other states.