LOS ANGELES — Leaders of the Iranian Jewish community say they are disturbed that a member of their community is believed to have been responsible for a string of arson attacks that targeted religious institutions, including synagogues.

At the same time, however, they expressed relief that the attacks apparently were not motivated by anti- Semitism.

Farshid Tehrani, 40, was arrested early last Friday by police, who had been tracking him for a day after receiving a tip linking him to the five arson incidents in Encino.

During three successive days last week, incendiary devices, described by some as Molotov cocktails, were hurled at the Baha'i Faith Community Center, the Iranian Synagogue, Da'at Torah Educational Center and Valley Beth Shalom, one of the leading Conservative congregations in the Los Angeles area.

About 10 days earlier, a similar attack on the First Presbyterian Church of Encino caused $75,000 to $100,000 in damage, according to the Los Angeles Times. Damage at the other locations was relatively minor, and there were no injuries.

Sam Kermanian, secretary general of the Iranian American Jewish Federation, said that his community, as "one of the targets of these attacks, had been extremely concerned that they were hate- or terrorism-related."

But relief over the arrest was mingled "with deep shock at the possibility that the perpetrator might be someone from our community.

"This obviously cannot be the work of a healthy mind," he added.

Tehrani apparently suffered from depression.

"It's disturbing that an Iranian Jewish immigrant is believed to be the perpetrator, but I understand that he had psychological problems," said George Haroonian, president of the Council of Iranian American Jewish Organizations, said. "You will find this in every community, and it tells us that we must try to identify such problems early on."

Pooya Dayanim, president of the Iranian Jewish Public Affairs Committee, urged government agencies to channel grants directly to the Iranian Jewish community to enable it to deal more effectively with mental and other health problems.

Investigation of the attacks was conducted through one of the largest local law enforcement mobilizations in recent history, with more than 150 police, fire department, FBI and other federal investigators working on the case. These included 65 detectives from the L.A. Police Department's anti-terrorism division.

Police said there was no evidence linking Tehrani to any terrorist groups or causes. One official described him to the L.A. Times as a firebug with serious personal problems.

"We probably saved a lot of lives in this one," the unnamed official said. "He was heading to something bad."

According to his immediate family, Tehrani came to the United States about 16 years ago and worked hard in his jewelry business in downtown Los Angeles, until a "depressive disorder" forced him to give up most of his work two years ago.

His younger sister, Sheena Tehrani, described her brother, who is unmarried, as "a kind, caring" man "who just got burned out. There has to be some mistake. He is not that type of person.''

Rabbi Moshe Hafuta of the Da'at Torah Educational Center told the Times that he had been involved in a dispute over an apartment he rented from Tehrani, and that a blaze, apparently set with lamp fluid, broke out at the apartment in late April.