An 87-year-old man visiting a family member at a convalescent home (search) allegedly shot a nurse Friday after he became angry about the care the relative was receiving, authorities said.

The nurse, who was shot at close range, was listed in critical condition at a nearby hospital, Riverside County sheriff's spokesman Dennis Gutierrez said.

Minutes after the afternoon shooting at the Ember Care Health Center (search) in Perris, authorities arrested Norman Larson of Sun City for investigation of assault with a deadly weapon, Gutierrez said. Center employees had detained Larson by the time deputies arrived.

"He had been there for about five hours," Gutierrez said. "He had an issue with the way the family member was being cared for."

A woman visiting the center said the gunman threatened to shot another nurse.

"He was going to shoot another nurse and made her get on her knees and beg for her life," Dalis Baca told KABC-TV. "When she pleaded, she said it was Christmas, she had kids, please not to do it, and he let her go."

Citing privacy laws, Gutierrez did not identify the family member. He said Larson and other visitors and patients were being interviewed by investigators.

The 104-bed home is one of 12 convalescent homes Ember Care operates in Southern California, said April Bernabe, vice president of operations.

Perris is about 70 miles southeast of Los Angeles.