NYC- A manhunt was on last night for a lecherous lawyer from a top-flight firm who allegedly paid a Manhattan mom so he could bed her teen daughters – one just 13.

Fugitive attorney James Colliton should have been in custody in New York – but he was sprung because of a paperwork snafu after Canadian officials nabbed him in Toronto and turned him over to U.S. Border Patrol agents, officials said.

“I want nothing more than for him to get caught and rot in jail,” one of the victims told the Daily News last night. “I’m afraid he’ll just buy his way out.”

She was 15 when she started having sex for money with the man she called “Big Jim” in 2000. The victim, now 21, sold herself to Colliton and her mother took a cut, prosecutors said.

A neighbor of the family’s on the West Side said she tried to care for the girls because their “evil mother” failed to properly clothe and feed them.

She said “Big Jim” would come by and pick up the girls in his Jaguar, and tell them his wife was dying of cancer – and promise they would get “all kinds of money” once she died.

“Their mother . . . said, ‘I never worked a day in my life. My kids work for me,’ ” the neighbor said.

Investigators fear Colliton, a married 41-year-old father of five from Poughkeepsie, had a stable of other girls he bedded in his secret E. 56th St. lair. Colliton – a tax attorney for the white-shoe firm of Cravath, Swaine & Moore – paid the 38-year-old mother’s rent and showered her and her daughters with gifts and cash in return for sex, prosecutors said.

“We’ve had a lot of wild cases, but this is one of the wildest,” said veteran Manhattan District Attorney Robert Morgenthau.

The suspect, an NYU Law School grad, allegedly offered the sisters bribes to keep quiet when authorities began asking questions last month, officials said.

When cops went to Colliton’s midtown pied- … -terre to arrest him Feb. 13, all they found was a note telling them to contact his attorney, Alan Abramson. Abramson did not return calls for comment yesterday.

The name of the mother, who was jailed on $100,000 bail, is being withheld to protect the identities of her daughters.

The sexual abuse came to light Feb. 9 when the younger girl told a social worker from the city’s Administration for Children’s Services her mother had prostituted her and her sister, prosecutors said.

The girl, now 14, told officials her mom sent her to live with Colliton at an apartment he kept on 56th St. near Lexington Ave. She said she was 13 when Colliton started paying her for sex, and that her mom took a cut.

“The investigation revealed that Colliton engaged \[in sex acts\] with her approximately five times a month in exchange for money,” Morgenthau said.

The girl told investigators she ran away from Colliton’s apartment – but her mom forced her to return to him.

Investigators said the girl was introduced to Colliton in 2004 by her older sister, who said she met the lawyer through her cousin, a 17-year-old stripper.

“Initially, the defendant gave the girl alcohol and marijuana, and then paid the young girl to engage in sexual acts with him,” Morgenthau said.

Colliton is charged with second-degree rape, patronizing prostitutes and bribing witnesses. He faces a maximum of seven years in prison.

The mother is charged with promoting prostitution and endangering the welfare of her children. She could get 15 years in prison, if convicted.

Officials said ACS had been involved with the family for years, and that in 2002 two children – including one of the sex-for-hire victims – had been removed from the mom.

The mother was later convicted of obstructing justice for swiping her children back and hiding them from ACS, officials said. Her conviction came with no jail time, and it was unclear whether she legally regained custody of her kids.

Steven Spiess, executive director of Cravath, Swaine & Moore, refused to comment yesterday except to say, “Mr. Colliton is no longer employed” with the firm.

Canadian officials said they arrested Colliton on an immigration warrant Friday night at a hotel near Toronto. Colliton was turned over to U.S. border agents Tuesday on the Rainbow Bridge in Niagara Falls.

“The American border agents were aware of the outstanding \[criminal\] warrant and charges facing the individual,” said Jean D’Anelio Swyer, spokeswoman for the Canadian Border Services Agency. “What happened after that, I don’t know.”

A high-ranking law enforcement source said Colliton was released after U.S. border agents contacted the NYPD and were told the warrant was suspended. Twenty-eight minutes later, NYPD officials were informed the warrant had been reinstated, but Colliton was gone.

Colliton’s midtown neighbors were stunned by the charges. “We saw him with a young girl, but we didn’t know if it was a friend, a girlfriend or if she was living with him,” one said.

Neighbors in Poughkeepsie said they would often see Colliton’s kids playing in the driveway of their two-story brick-and-vinyl house, but he was rarely around.

“It’s too bad. He has little kids,” said one neighbor.

Back story: The big bucks lawyer who allegedly paid to have sex with two sisters kept a harem of underage girls for his pleasure, one of the siblings told the Daily News yesterday.

The victim, now 21, said slick-talking James Colliton “manipulated” up to 10 other girls into spending time with him in a seedy studio apartment he kept as a sex den.

She said she first hooked up with Colliton when she was 15 and that her sister was just 13 when he got his hands on her.

“But we weren’t the only girls. There were others, and they were young when they started, too,” she said.

The woman, who spoke with the understanding that her name would be kept secret, blew the whistle on Colliton’s alleged depraved doings.

“I just want him to be in jail forever for what he did,” she said.

The victim said Colliton paid for sex acts with money, jewelry and such things as a television, a computer and rap concert tickets.

Her mother took half of the money she got from the lawyer and all of the presents, the woman said.

“He’s mostly at fault,” the victim said. “She did wrong, but I don’t hate her. She gave me life. She’s still my mother.”

The woman said that until she ran away from home a year ago, her mother would call Colliton and say she needed “four or five hundred dollars … for the car, the house, for expenses.”

The lawyer would send a car or a taxi for her.

“I was paid three or four hundred, depending on what I had to do … and I had to do nasty things,” she said.

The woman said she brought her kid sister to Colliton’s sex nest for a few weeks, hoping that the sister’s presence would discourage the lawyer from hitting on her. When it didn’t, she brought her sister back to her mom.

She said when she learned her mom had prostituted her sister to Colliton, she decided to bring the girl to authorities and tell them what was happening.

The woman said her only regret was that her mother was arrested. “That wasn’t our intention. She needed the money we got her.”