LOS ANGELES (CNS) — A convicted sex offender from North Hills who was spotted photographing children at a Granada Hills strip mall has been sentenced to more than seven years behind bars for possession of child pornography.

Warren Alec Johnson, 57, was also ordered to serve under supervised release restrictions for the rest of his life following his 87-month term in federal prison. He was also ordered to pay restitution to one child identified in the child pornography.

Johnson pleaded guilty last year to possession of a compact disc containing illicit images involving a minor under the age of 12. He also admitted to “stalking behavior,” according to the government’s sentencing memorandum filed in Los Angeles federal court.

The case began in October 2014 when Johnson, a construction worker, was spotted taking photos of children attending an elementary school fundraiser at a restaurant in a Granada Hills strip mall. A person at the event became suspicious and contacted authorities.

Days later, a child sex abuse task force composed of FBI agents and Los Angeles police officers searched his home and found the disc along with illegal weapons. He was then taken into custody on suspicion of child annoyance.

Federal prosecutors said they found no evidence that Johnson made contact with any of the children he photographed.

Johnson was previously convicted in 2008 of possession of child pornography.