The police in California and the Federal Bureau of Investigation on Sunday opened a hate crimes investigation after two mosques were vandalized overnight, the latest in a series of episodes of vandalism and arson at Muslim and Sikh houses of worship in Southern California since the terrorist attack in San Bernardino.
Worshipers arriving on Sunday morning at the Islamic Center of Hawthorne found the words “Jesus is the way” spray-painted on the building, said Sgt. Christopher Port, a spokesman for the Hawthorne Police Department.
The word “Jesus” was also spray-painted in white on an outer wall of the Ahmadiyya Muslim Community Baitus-Salaam Mosque in Hawthorne, he said, and an object resembling a hand grenade was found in its driveway. The object was found to be “a plastic replica,” said Sara Rodriguez, a spokeswoman for the Los Angeles County Sheriff’s Department.
The Los Angeles field office of the F.B.I. joined the investigation on Sunday, the Hawthorne police said.
The vandalism in Hawthorne came two days after Carl James Dial Jr., 23, was arrested in nearby Riverside County and charged with arson, hate crime and burglary after the police said he set fire to a mosque, the Islamic Society of Coachella Valley, in Coachella.
The fire began 15 minutes before the start of a midday prayer service, and several worshipers were inside the building when emergency crews arrived.
“We were just here trying to be free and practice our religion just like everybody else,” Salahaldeen Alwishah, 27, who was inside the mosque when the fire started, told The Los Angeles Times.
The Riverside County Sheriff’s Department said that the fire was quickly brought under control and that no one was injured.
Two days before the fire in Coachella, the police in Buena Park, Calif., opened a hate crimes investigation after a Sikh temple was vandalized.
Expletive-laced graffiti was sprayed on walls in the parking lot of the temple, Gurdwara Singh Sabha, as well as on a tractor-trailer parked there, said Jaspreet Singh, a board member of the temple.
“The graffiti had gang codes and a racial slur and profanity in reference to ISIS and Islam, which was misspelled,” he said in an interview last week, using an acronym to refer to the Islamic State.
The Sikh religion is entirely separate from Islam, but Sikh men, who wear turbans and long beards, have often been the target of anti-Muslim crimes.
Ibrahim Hooper, a spokesman for the Council on American-Islamic Relations, an advocacy group, said the country had experienced “an unprecedented spike in anti-Muslim incidents” since the Paris and San Bernardino terrorist attacks.
“Normally we would issue statements on each and every one of these attacks, but now we don’t even have time to do that because there have just been so many,” Mr. Hooper said, referring to the work of his organization.
He said that anti-Muslim rhetoric from presidential candidates like Donald J. Trump and Ben Carson had contributed to an increasingly hostile environment for Muslim Americans.
“Right after 9/11, anti-Muslim hate was on the fringes of society, and now it has been brought right into the mainstream,” he said. “It’s almost acceptable now to hate Islam and Muslims, and now we see the results.”
On Sunday, the Hawthorne police evacuated the area around the Ahmadiyya Muslim Community mosque, including two nearby residences, while a Los Angeles County Sheriff’s Department bomb squad responded to the scene, Sergeant Port said.
Sergeant Port said the police believed the vandalism at the Ahmadiyya Muslim Community mosque “happened in the early morning hours at some point overnight.” Officers responded to a call from the scene shortly after 6:30 a.m.
Dr. Ahsan Khan, a spokesman for the Ahmadiyya Muslim Community mosque, said that in addition to the word “Jesus,” there were three crucifixes spray-painted on the wall of the mosque. “This was a hate crime, by all indications,” he said.
“Like everyone else in Los Angeles, members of our community were shocked by what happened” in San Bernardino, Dr. Khan said. “We were saddened that these terrorists did this in what they professed to be the name of Islam.”