Kennedy, who is jailed on probation violations for simply being associated with a child, works with cement in the area where the body was found, according to the family's statements to WXYZ.
Whoever the killer is, Sherry Buchanan told the station, "I hope they give him everything that's got coming to him."
"I told the officer, I said, 'You're not going to be able to protect him,'" she said. "I said 'One way or another, I said, I am going to get to him."
In addition to Kennedy, police have also named a second person of interest in the case, another sex offender who knew Jennifer Buchanan. That man, Roy Lee Smith, 48, was released from prison last year after serving 15 years for multiple criminal sexual misconduct convictions, according to the Michigan Department of Corrections Web site. Other convictions include mulitple counts of larceny.
He, too, was jailed for probation violations.
When asked last month if Buchanan herself was a person of interest, Crutchfield replied "no comment," according to ABC affiliate WXYZ.
Smith's mother, Donna Smith, told ABCNews.com last month that her son is not involved in Neveah's disappearance.
"I don't believe my son has anything to do with this," Donna Smith said, adding that his previous conviction was because a 24-year-old girl he was with "decided to holler rape."
A bloody towel and a blood-stained tool, along with photos of young girls, were among the evidence confiscated from Kennedy's motel room and in a van that also has ties to Smith.
Donna Smith said her son had traded the van to Kennedy about a week and a half ago and got Kennedy's Thunderbird in return.
Crutchfield said police had received about 530 tips in the case.
Monroe County police spokesman Maj. Dan Motylinski told ABCNews.com last month that they will follow up on every tip that comes in.
"All we can do is hope it's a recovery of her alive and well," he said.
He declined to comment on reports from the Detroit Free Press that Buchanan told reporters that investigators had seized a letter she had written to Kennedy, but tore it up before it was sent.
She told the newspaper the letter was completely innocent and that it made no mention of Neveah or Kennedy spending time with her.
In 1998, Kennedy, 39, was charged with a felony for having sex with a girl under 16. That charge was later dismissed, court records show.
In addition to the 1998 charge, court records show that by 2002, Kennedy had been charged with a home invasion and accosting a 13-year-old girl. Kennedy's former court-appointed lawyer Peter Sickels told ABCNews.com that the charges were combined in a plea deal that allowed him to be released from prison in 2003.
The Associated Press contributed to this report.