A sex offender admitted Wednesday that he had lied on forms to get a job as a U.S. Census taker, blaming it on a series of mix-ups and his desperation to get a job.

Frank Kuni could face up to 16 years in federal prison, though a much shorter term is likely when he's sentenced on March 2.

His deception came to light early in May.

A Pennsauken woman at home with her toddler recognized Kuni from an online registry of sex offenders, in part because he was said to have 16 aliases, including amusing ones such as "Phanton Flam" and "Toot Flynn." She called police and Kuni was arrested.

At about the same time, the U.S. Census Bureau was on his trail after getting fingerprint results that showed he wasn't 37-year-old Jamie Shepard, as he said he was, but rather 47-year-old Frank Kuni, who was convicted in 1996 for sexually assaulting a girl and having inappropriate contact with another.

A prosecutor told U.S. District Judge Noel Hillman on Wednesday that both his lies and his criminal past were grounds for firing him from his job going door-to-door collecting data. The Pennsauken resident held the government job only a few days before he was dismissed. He's been in custody since his arrest.

Kuni's guilty plea Wednesday was protracted because he wouldn't admit to everything he was accused of doing. It took Hillman some weighing before accepting the deal in which Kuni pleaded guilty to four counts out of the 13 initial charges.

At one point, a frustrated Hillman told Kuni, "I will not take a plea from someone who is not willing to admit all the elements of the offense."

All the counts related to lying to the government.

Kuni said he gave the name Jamie Shepard because that's what he went by — and is even the name on his only Social Security card. He said he didn't realize that a name-change application to make him officially Jamie Shepard hadn't gone through.

"The government issued me a Social Security card" with the fake name, he said. "I was between a rock and a hard place."

He also denied giving a wrong Social Security number, saying the problem was that someone misread his admittedly sloppy "9'' as a "7."

He admitted he gave a falsified identification card — a Burlington County College ID with an added expiration date. He said that was because he was told the card had expired.

He also said he didn't report a 2002 drunken driving conviction, but didn't offer a reason. He also didn't explain why he gave his birthday as June 12, 1972, when he was really born in 1962.