A northern California police department put one of its officers on leave on Monday and is investigating threatening comments from his Twitter account about demonstrators who have participated in protests over the recent deaths of unarmed black men in Ferguson, Missouri and New York.

The San Jose police department said officer Phillip White was sidelined after officials learned of statements made on Saturday from his Twitter account.

In the tweets, White said he would kill anyone who threatens him or his family. He also said he would be off-duty at the movies with his gun if anyone “feels they can’t breathe or their lives matter”.

The tweets and hashtag played on protest slogans “I can’t breathe” and “black lives matter”.

Efforts to reach White through the San Jose police officer’s association were not successful.

The tweets and White’s Twitter account have been deleted amid a social media firestorm over the comments. White’s department, union and a college where he coached basketball all condemned the comments.

“It is extremely important for the community to know the comments made on Officer White’s private social media account do not reflect the thoughts or feelings of the men and women here at the San Jose police department,” San Jose’s police chief, Larry Esquivel, said.

The department said it has received “numerous media inquiries” about White since the online news site Buzzfeed reported the officer’s tweets on Sunday.

“Offensive, disrespectful and inappropriate social media comments have no place in the public discourse surrounding the tragic loss of life from recent officer involved incidents,” the San Jose Police Officers’ Association said in a prepared statement. “We condemn these comments.”

Menlo College, a small private school about 25 miles south of San Francisco, cut ties with White, who served as a paid, part-time assistant basketball coach.

“The college will not be represented by expressions of intolerance and bigotry on the campus, on social media, or on the internet,” the college said in a statement.

The San Jose Mercury News in October wrote about the 20-year veteran’s success with a gang prevention education program for schoolchildren. The paper reported that the program was widely regarded for addressing life issues with youngsters, including choices and consequences, peer pressure and bullying and harassment prevention.

White was described as “really dynamic with the kids” in the story. The paper also described him as a “positive role model” for the children enrolled in the gang prevention program.