VISTA — In the midst of his trial, the head of a North County robbery ring pleaded guilty Aug. 19 to multiple robbery charges relating to a string of holdups last summer.

Facing life in prison, Thomas Graham, 33, took a plea deal admitting to the robberies of three day laborers at knifepoint. He is expected to receive 13 years in prison and be given his second strike when he’s sentenced Sept. 18, Deputy District Attorney Bryn Kirvin said.

Twelve counts of robbery, as well as three other felony charges — kidnapping, attempted kidnapping and attempted robbery — were dismissed.

Kirvin said she felt the plea agreement represented a “fair resolution” between both parties. Some of the evidence, she said, in particular the victims’ accounts of the robberies, was stronger than other pieces.

Defense attorney Herb Weston told the jury in his opening statement that he believed there would be issues with the victims’ identifications of his client due to misconceptions by the day laborers, some of whom are illegal aliens, about obtaining citizenship.

Graham, of Escondido, was the last of four defendants to plead guilty to the series of robberies involving day labors from sites in Encinitas, San Marcos, Rancho Bernardo and Vista, Kirvin said. The victims were taken to remote areas in North County and robbed at knifepoint of their money and belongings, she said.

Nicole Dianne Couch, Kevin Anderson and April Lewis all pleaded guilty to two counts of robbery. Couch and Lewis were sentenced to five years in prison, while Anderson received two years in prison.

Graham was considered the most culpable of the group because he always had the knife, Kirvin said.