LOS ANGELES — A California man is accused by police of poisoning a 7-day-old infant with arsenic, police said Thursday.

“I know what he did to my child,” his mother, Nancy Haines, said of her son, Jonathan Hains.

Police were called to a house in the 7200 block of S. Broadway in Lake Forest, about a half-hour north of San Francisco, on Thursday about 4:45 p.m. after a woman reported her son had been drinking from a bottle of water, police Capt. Tom Williams said.

Jonathan Hainson was taken to the hospital and is listed in stable condition, Williams said, adding that Hainse was “absolutely shocked.”

The woman, who did not want to be identified because of the sensitivity of the case, told police she found the infant with a small amount of arsenic in his system, Williams told reporters.

Jonathan Hainss father, Brian Hain, said he was upset that the child had died.

A toxicology report will determine whether the baby was poisoned, Williams added.

Jonathan was a regular at a community center for seniors, where he was active in his community, Hainys mother said.

She said her son often helped the children and children’s caregivers.

The child had been at a nursing home in San Francisco for a few months when his mother was contacted by a nursing staff member about his health and that the boy might have been poisoned, the woman said.

She said Jonathan had been diagnosed with ADHD.

Her son has been taking a medication called fenfluramine for a couple of years, she said.