Sean Bianchi positioned his undercover car near the target house, a pear-green triple decker on Blue Hill Avenue, and he strategized with other US Marshals and local and State Police who were waiting nearby, but all they had at this point was a picture.
Anton Febles had been convicted a decade ago of indecent assault and battery on a teenager. He had been designated a Level III sex offender, the class most likely to reoffend. And still he had failed to register with authorities. Even worse, police were told that he may be carrying a gun, and Bianchi suspected he was hiding inside.
“He sounds like he’s a little more desperate now,” said Bianchi, a 39-year-old deputy US Marshal assigned to the Fugitive Task Force’s Sex Offender Apprehension Program, or SOAP.
So they waited, as the rain began to pour, for any sign that Febles was leaving the house, or any chance for them to enter: They monitored the front stairway, the rear porches, and the blue 2001 Subaru Legacy that was parked nearby.
“He’s got to be there,” Bianchi said impatiently.
Through the SOAP, Bianchi and the US Marshals Service have created a partnership with Boston police, a first-of-its-kind, full-time task force that tracks down convicted sex offenders like Febles who have failed to register with state authorities.
The unit was enacted under the mission of the 2006 Adam Walsh Child Protection and Safety Act, and it has become increasingly active in recent years as federal officials ramp up efforts to target sex offenders like rapists, sex traffickers, those involved in child pornography and the exploitation of children.
“These sexual predators — that’s what they are, predators — will go anywhere, across state lines, across the world, and it’s important that we have these partnerships of Marshals and local and State Police tracking them,” said US Marshal John Gibbons, representing Massachusetts.
The Sex Offender Registry Board in Massachusetts, which classifies the dangerousness of offenders, welcomed the collaboration, too, saying efforts to apprehend violators “is vital to protect the citizens of Massachusetts.”
“The law requires sex offenders to comply with registration obligations by providing accurate, updated offender information, which helps prevent further victimization of children and other vulnerable populations,” said Saundra Edwards, chair of the Sex Offender Registry Board.
Since 2007, the Massachusetts-based unit has arrested 565 people on warrants for failing to register as sex offenders. And those numbers have risen sharply in the last three years since the partnership with Boston police was forged: The unit made 57 arrests in 2011, compared with 71 in 2012 and 84 in 2013, and already more than 50 arrests have been made duirng the first half of the 2014 fiscal year.
The offenders, who are initially wanted on state warrants, but who can be prosecuted federally if they cross state lines and fail to register, are considered the most likely to reoffend.
Some of the offenders recently captured include:
■ Terrance Brown, convicted in 2004 of indecent assault and battery on a 14-year-old, raised suspicions when he later traveled to North Carolina with a child. He was convicted in federal court of failing to register as a sex offender, and was sentenced in 2012 to two years in prison, followed by 10 years of probation.
■ Stephen Mitchell was convicted in 1995 of indecent assault and battery on a 12-year-old, and was charged in state court in 2009 with rape of a child and disseminating obscene material to a minor. He fled the 2009 charge, and was tracked down in Georgia. He was sentenced to two years in federal prison for failing to register as a sex offender, and ultimately pleaded guilty and was sentenced to four years for the 2009 charge of rape of a child.
■ Gary Dixon was convicted twice of indecent assault and battery on a child under 14, in 1987 and 1993, as well as open and gross lewdness, but he failed to tell that to authorities in Maine, where he had been living with his new girlfriend. He was found and arrested, and pleaded guilty in federal court in Boston to failure to register as a sex offender, and is slated to be sentenced June 4.
“This is what this law was meant for, to go after those who are intentionally trying to evade their responsibilities,” said Timothy Orava, a deputy US Marshal assigned to New England. He works with Bianchi, the deputy Marshal who focuses on cases in Massachusetts, and Boston Police Detective Sergeant Rick Johnson, who is assigned to the unit full-time.
The three of them, each of them fathers, said the mission of their unit has become clear under the Adam Walsh Act, which was named after a boy who was abducted and murdered in Florida in 1981.
“We’ve read enough about what these guys have done in the past, the ages of these kids,” said Johnson, a street cop by nature who tries to engage the offenders. “Some of these guys, they say they forgot, or they were going to do it when they got themselves together. Some of them, they just don’t want to do it, they’ve convinced themselves they didn’t do it, and I think that’s what the Adam Walsh Act was for, that kind of activity.”
Bianchi added, “They’ll go anywhere to evade arrest, that’s the nuts and bolts of it. They’re trying to fly under the radar, and it’s alarming. . . . Who wouldn’t want to go after these offenders?”
Last week, they had finally tracked Febles’ trail, through Dorchester and into Mattapan, where the Subaru legacy the 28-year-old has been driving recently was parked.
Febles had been charged in 2005 with aggravated rape of a teenager, though he eventually pleaded guilty to a lesser charge of indecent assault and battery, and he was sentenced to 2½ years in prison followed by five years of probation. He now had a warrant for his arrest.
Bianchi struggled with the situation outside. “I know he’s there,” he said.
After two hours of waiting, the deputies and police were able to get inside the apartment house, and eventually into the third-floor unit. Febles, who had evaded them for hours, finally walked out, apparently defeated.
“He just gave up, and came out,” said Jimmy Hui, a deputy Marshal.
Milton J. Valencia can be reached at mvalencia@ globe.com.