A suspect arrested for stealing a Lexus belonging to Mayor Bloomberg and assaulting one of his personal aides pleaded guilty this week in New Jersey to first-degree carjacking charges, officials said.

In the guilty plea, Shawn Young, 35, agreed to the state recommended sentence of at least 15 years in prison for carjacking Mr. Bloomberg’s 2001 Lexus LS430 in October 2006 in Hackensack, N.J., an incident that left an aide, Gladimir Bosnjak, 62, with a black eye. Young’s accomplice, Evelyn Moretta, 18, pleaded guilty to first-degree carjacking in December, agreeing to a recommended sentence of at least 10 years in prison. Judge Harry Carrol will officially sentence the two during separate sentencing hearings in Bergen County that are scheduled in the next few weeks. As part of the plea deal, both defendants will serve be required to serve least 85% of their sentences before they can be up for parole.

“The mayor appreciates the hard work of the law enforcement officials on this case,” a spokesman for the mayor, Stuart Loeser, said. The two defendants assaulted Mr. Bosnjak on October 18, 2006, while he was picking up another one of Mr. Bloomberg’s employees in Hackensack.

Moretta approached the window of Mr. Bosnjak’s car and asked for $5, Hackensack police told several press outlets. When Mr. Bosnjak refused, Moretta snatched his keys, while Young jumped into the vehicle and punched him in the face.

The pair then pushed Mr. Bosnjak out of the car and drove away. Police found the vehicle several hours later in a neighboring town.

Mr. Bosnjak refused medical attention and did not speak to reporters outside of his home in Queens after getting dropped off later that evening.

Investigators first captured Moretta, who at the time of the incident was a minor. Moretta then gave up Young, who police found in jail after he had been picked up for failing to pay child support.