The FBI task force that helped find and rescue Philadelphia kidnap victim Carlesha Freeland-Gaither has joined the search for missing college student Shane Montgomery.

As agents began reinterviewing witnesses in the Manayunk area Sunday, a police marine unit ended its inch-by-inch search in the frigid Manayunk Canal, failing to turn up any trace of Montgomery. The marine unit may next begin searching the nearby Schuylkill.

Montgomery's mother, Karen, said she felt bittersweet relief that her son had not been found in the murky canal.

"Today I'm OK, because I know that Shane is not in that water," she said.

A law enforcement source with detailed knowledge of the investigation said the FBI was questioning the staff at Kildare's Irish Pub, where the West Chester University student, 21, was last seen early Thanksgiving Day, after partying with friends.

Kildare's, at 4417 Main St., is within feet of the canal and the Schuylkill.

A bar bouncer told Montgomery to leave after he accidentally tripped into a DJ booth, police said. The bouncer and Montgomery's cousins had told investigators he was "not falling-down drunk."

"The bouncer says he spoke to him, and Shane apologized and left," the investigator said. "There is no indication that he was staggering."

He went out into freezing conditions wearing a gray button-down shirt, blue jeans, and a hooded sweatshirt for warmth. Until Sunday, the region's temperature had stayed near freezing or below since Wednesday's snowfall.

"He left his fleece-lined jacket at home," his mother said, her eyes filling with tears. "I saw it at the house, and it broke my heart."

Tired and anxious volunteers, friends, and relatives waited Sunday in the basement of St. John the Baptist Church as the canal search slogged on. Since Montgomery was reported missing Thanksgiving Day, nearly 500 volunteers have covered 475 acres in an exhaustive search, scouring footpaths, the riverbank, and along the rusted railroad tracks that parallel the canal.

By midafternoon Sunday, Karen Montgomery said she would disband the search effort. Many of the volunteers were college students who needed to return to class on Monday, she said.

The FBI task force is the one that helped find Freeland-Gaither within 72 hours of her abduction last month. The nurse's assistant was grabbed by a man later identified as Delvin Barnes, 37, now charged in the case.

In Montgomery's disappearance, federal agents began reinterviewing possible witnesses, including the staff at Kildare's, and looked for video that may have captured images of Montgomery as he left the bar.

Investigators said that there was no video from the bar that night and that no other video clearly identified him.

At first, investigators believed a grainy video from a nearby surveillance camera showed an altercation outside Kildare's around the time Montgomery was thrown out. But an analysis showed the video merely captured crowds of bar revelers milling about, trying to hail cabs, they said.

"It's nothing we're going to call an altercation," one investigator said. "There is no video that you can distinctly say, 'That's Shane, and that's the direction he's heading,' so it's very frustrating.

"He leaves the bar and disappears into thin air," the investigator said.

He said the FBI might administer polygraph exams to some of Kildare's staff and other witnesses. The bar staff has been cooperative, he said.

"It's not that we don't believe them - we have no feeling the bouncers or anyone is lying, but we want to cover all our bases, so we don't miss anything."

Detectives from throughout the city have volunteered in shifts to help with the search and to conduct follow-up interviews. A command center was set up at a fire station on Main Street.

Investigators have searched Montgomery's home bedroom in Roxborough and his West Chester dormitory room. They have combed the bar for evidence, interviewed taxi companies that had cabs in the area Wednesday night, and searched morgues and hospitals. Police in nearby Lower Merion were asked whether they had encountered Montgomery.

Aviation units were brought in to search parks, rooftops, and nearby train tracks and search dogs have scanned the canal and river banks.

After family members identified Shurs Lane, which intersects with Main Street about a half-mile from the bar, as a route Montgomery might have used to walk home, relatives and volunteers combed the path, searching alleyways, trash bins, cars, and wooded areas.

"We will keep plugging away till something gives," the investigator said. "We're not going to give up until we find something."

Police marine units entered the cold canal early Sunday, using poles to search the bottom. Wearing bright-yellow waterproof waders, the seven searchers moved slowly in a line along the canal, which skirts the Schuylkill.

The painstaking exploration plodded through brown water sometimes chest deep, sometimes knee deep, as joggers and dog-walkers passed by on the foot trail.

The somber work moved methodically away from Kildare's. Montgomery's father, Kevin, 56, and his mother watched from the canal bank.

"It's amazing what these men are doing," Karen Montgomery said. "They are working so hard, and we are so grateful."

Just before 2 p.m., investigators said the search was futile.

Karen Montgomery said she had racked her brain for any possible explanation of her son's disappearance. He had walked a little more than a mile home from Manayunk many times, a walk of no more than 35 minutes, she said.

His last cash withdrawal was made well before he left Kildare's, she said. The last text message he sent from his cellphone was at 1:15 a.m., to his cousin after they were separated in the crowded bar. His last phone call was at 1:28 a.m., made to a friend just before he left the bar.

The last cellphone ping, from a tower in Lower Merion at 2:38 a.m., put Montgomery within 4,500 feet of the CVS pharmacy on Main Street, a little less than a mile away. That radius could stretch as far as Henry Avenue, police said.

As police worked, the sound of Christmas carols filled the air from speakers on Main Street and locals sat down for Sunday brunch and ducked in and out of shops.

Blocks away, parishioners arrived for Mass at St. John the Baptist Church on Rector Street, where searchers have been based for three days. Searchers sat in the church basement, drinking coffee and waiting for any news.

Montgomery's family again asked anyone to come forward if they may have seen Montgomery that night, noting that he had last been spotted on a busy street on one of the biggest bar nights of the year.

"I believe someone saw something that could be significant, even if they don't know whether it's significant," said Montgomery's aunt Marianne Whittman.

The family has offered a $10,000 reward for information about his disappearance. The Fraternal Order of Police has added $5,000 to that reward amount.

Hundreds of volunteers huddled at an emotional prayer vigil across the street from Kildare's on Saturday night after Manayunk's Christmas tree lighting and caroling were postponed. A special Mass followed at St. John the Baptist.

Nearly 500 people - friends, family, fellow students, and neighborhood residents - had searched the streets and the Schuylkill riverbank in bitter cold over two days.

Montgomery, a graduate of Roman Catholic High School, is white; 5 feet, 11 inches tall; and weighs about 130 pounds, with short brown hair, green eyes, and a Celtic cross tattoo on one shoulder.

Anyone with information is asked to call Detective Patrick Valentino at 215-686-3353 or 3354.

Photos of Montgomery and his tattoo can be viewed at