Presidential assailant John Hinckley Jr. (search) has a troubling relationship with a former girlfriend that must be resolved before he can be allowed to spend more time away from a psychiatric hospital, a government expert testified Tuesday.

The testimony came on the second day of a hearing to determine whether Hinckley is ready to spend several days at a time away from St. Elizabeths, the Washington mental hospital where he has lived since he tried to assassinate President Reagan in 1981.

Federal prosecutors have argued that Hinckley's relationship with Leslie DeVeau (search), the former girlfriend, is "disturbingly unclear." DeVeau is a former patient at St. Elizabeths who spent eight years at the hospital after she was found innocent by reason of insanity in the killing of her 10-year-old daughter.

Hinckley and DeVeau had a romantic relationship while both were at the hospital, but DeVeau broke it off several years after she was released in 1990. Since then, she and Hinckley have remained close friends, but prosecutors say it is unclear whether Hinckley has come to terms with the breakup. The two still talk on the phone twice a day and she visits him once a week.

Robert Phillips, a forensic psychiatrist, told a federal judge that unresolved questions about the relationship could cause Hinckley psychological stress while he is in the public eye.

"In Mr. Hinckley's case, relationships have been one of the most important factors that have come to the foreground when he has been most clinically dysfunctional," Phillips told U.S. District Judge Paul Friedman.

Hinckley has said he shot Reagan to impress actress Jodie Foster (search). He was acquitted in 1982 by reason of insanity, and his lawyers argue that he no longer poses a danger. He gradually has won permission to leave hospital grounds, first with escorts and then for short, unsupervised visits with his parents.

In his latest request, Hinckley wants permission to stay four nights at his parents' home in Williamsburg, Va., every two weeks. Officials at St. Elizabeths suggested instead that Hinckley spend Thanksgiving and Christmas with his family this year before being granted regular visits. Federal prosecutors oppose both plans.

Earlier Tuesday, Paul Montalbano, a forensic psychologist at St. Elizabeths, said Hinckley would pose no danger if allowed out for longer unsupervised visits. He said the outings are important to Hinckley's therapy and have improved his outlook on life.

Government lawyers also raised questions Tuesday whether Hinckley's parents, both well into their 70s, might have difficulty supervising Hinckley on more extended visits. Hinckley's sister, Diane Sims, took the stand to say that she could help supervise her younger brother on longer visits.

A psychiatrist and psychologist who treated or evaluated Hinckley testified Monday that he is a responsible patient, follows rules and has been forthcoming with his therapists.