A serial killer handyman has pleaded guilty to the murders of three elderly women who lived in his New York apartment building. Kevin Gavin, a 71-year-old from Brownsville, Brooklyn, would gain the trust of these elderly neighbors to help with repairs and errands and then brutally murder them in their own homes, according to prosecutors. “This defendant exploited elderly women who trusted him, gained access to their homes, and murdered them in a series of brutal attacks that shocked the conscience,” Brooklyn District Attorney Eric Gonzalez said in a press release . Gonzalez said Gavin “acted as a serial killer inside his own apartment building.” He added, “These victims were vulnerable neighbors who deserved safety and dignity, and instead had their lives stolen by someone they believed was there to help.” Gavin pleaded guilty Friday to one count of first-degree murder and three counts of second-degree murder in exchange for a promised sentence of 30 years to life in prison .…