The reward money has jumped to $37,000 for helping authorities nab the man responsible for a series of stranglings in Kensington.

The city is putting up $25,000 to help solve the cases, Mayor Nutter announced at a morning news conference attended by Police Commissioner Charles Ramsey, District Attorney Seth Williams, members of the FBI, and other city and law-enforcement officials.

Previously, the sole reward was $4,000 in the strangling death of Elaine Goldberg, 21, who was found Nov. 3. That reward was posted by the Citizens Crime Commission of the Delaware Valley, which is upping its contribution to $5,000.

Those rewards are dependent on tips that lead to a conviction, but the balance - $5,000 from the Fraternal Order of Police and $2,000 from Councilman Frank DiCicco - is offered simply for an arrest.

"Once he's brought in, if the DNA matches, you're paid," John McNesby, president of FOP Lodge No. 5, said at the 11 a.m. news conference at 1900 E. Cumberland St. in Kensington.

Citizens, however, should refrain from getting personally involved. Call 911, don't try to be a vigilante or a hero just you see someone resembling the widely circulated sketch of a suspect, authorities said.

That man might not be the killer, since depiction is based on possibly unrelated assault cases.

DNA tests showed that the same man sexually assaulted and killed both Goldberg and Nicole Piacentini, 35, who was found Nov. 13.

Soon, lab results should show whether the latest strangling victim, Casey Mahoney, 27, of East Stroudsburg, Pa., was killed by the same attacker.

Anyone with information on the case is asked to call homicide detectives at 215-686-3335 or -3336, the Philadelphia Police Department's anonymous tip line at 215-686-8477 (215-686-TIPS) or the Citizens Crime Commission at 215-546-8477 (215-546-TIPS).

Contact staff writer Allison Steele at 215-854-2641 or pmucha@phillynews.com.