BOSTON (CBS) — Victims of a level 3 sex offender living in Boston are learning more about his whereabouts. “I was a child whose friends were preyed upon by this man,” said Melanie Perkins McLaughlin.

Perkins McLaughlin is an advocate for victims of sex offender Wayne Chapman. She’s been closely watching his status on the sex offender registry since his release from prison in August.

“What about the rights of his victims and the people that he’s offended?” Perkins McLaughlin asked.

Chapman, 71, served 30 years for five convictions involving child rape. This week his whereabouts on the registry updated from “on the street” to now include “112 Southampton St., Boston.” It’s an address for a homeless shelter in Roxbury.

“The good news is we at least know where he is so we can all do a better job avoiding him,” said victims advocate Wendy Murphy.

As of Nov. 15, 662 level 2 and level 3 sex offenders were listed as either living or working in Boston. 172 are listed as homeless; 42, including Chapman, are listed at the same Roxbury shelter.

“There is very little oversight, very little confidence that they’re actually living there, and that’s a problem,” Murphy said.

Mayor Marty Walsh said the police department works closely with the courts and health department to keep track of the offenders.

“If we have someone registered as a sex offender within the public health commissions homeless facility, we make sure the police know about it and we want to make sure the community is safe,” said Walsh.

“Not only is the tracking them down a part of it, but then there is an investigation that has to happen,” said WBZ Security Analyst Ed Davis.

Davis said sex offenders registering as homeless is a complex problem that strains limited law enforcement resources.

“This is a systemic problem that needs to have attention and funding,” Davis said.

Homeless sex offenders must check-in with police every 30 days. The sex offender registry can be checked at anytime online.