NEWARK, N.J. (AP) — An inmate who fatally beat and choked his cellmate at a county jail has been sentenced to 29 years in state prison.

Rahdi Richardson had pleaded guilty to aggravated manslaughter in the 2013 death of 27-year-old Desmond Sanders at the Essex County jail. The plea came during the first day of jury selection for Richardson's trial.

The 34-year-old Newark man had tried unsuccessfully to withdraw his plea earlier this year. The sentence he received Monday will run concurrently with a 15-year term he's serving on armed robbery charges.

Sanders was found dead in his cell. He and Mitchell were both being held in connection with the June 2013 armed robbery to which Richardson also pleaded guilty.

Authorities have not said what sparked the fatal attack.