KAMPALA, Uganda — A prominent Ugandan gay rights activist whose picture was published by an anti-gay newspaper next to the words "Hang Them" was bludgeoned to death after receiving multiple threats, officials said Thursday.

David Kato, an advocacy officer for the gay rights group Sexual Minorities Uganda, was found with serious wounds to his head at his home in Uganda's capital Kampala, late Wednesday, a police spokeswoman said. Kato later died from his injuries on the way to hospital, police said.

"We cannot confirm that Kato was killed because he was gay or whether it was just an ordinary crime," police spokeswoman Judith Nabakooba said. Investigations were under way and no arrests had yet been made, she said.

A Ugandan tabloid newspaper called Rolling Stone listed a number of men they said were homosexuals last year, including Kato. Kato's picture was published on the front page, along with his name and a headline that said "Hang Them." A judge eventually barred the tabloid from printing such stories and photos.

Homosexuality is illegal in Uganda and gay men and women face regular harassment. A controversial bill introduced in 2009 and still before the country's parliament would see the death penalty introduced for certain homosexual acts. The bill prompted international opposition and it hasn't come up for a vote.

Human Rights Watch said in a statement Thursday that witnesses had told police that Kato was hit twice on the head by an unknown assailant who had been spotted entering his property. The assailant was then seen leaving by vehicle, the statement said.

The rights organization called for an urgent investigation into Kato's murder, saying that his work as a prominent gay rights campaigner had previously seen him face threats to his personal safety. The organization called on the Ugandan government to offer gay people in the country sufficient protection.

"David Kato's death is a tragic loss to the human rights community," said Maria Burnett, senior Africa researcher at Human Rights Watch. "David had faced the increased threats ... bravely and will be sorely missed."

Kato and two other gay activists sued the newspaper over claims that it had violated their constitutional rights to privacy and won the case earlier this month. A judge issued an injunction banning the publication of the identities and personal details of alleged homosexuals.

Frank Mugisha, the chairman of Sexual Minorities Uganda, said he has asked religious leaders, political leaders and media outlets to stop demonizing sexual minorities in Uganda since doing so creates a climate of violence against gay persons.

"Across the entire country, straight, lesbian, gay, bisexual, transgender and intersex Ugandans mourn the loss of David, a dear friend, colleague, teacher, family member and human rights defender," said Mugisha, who said Kato had been receiving death threats since his face was on the cover of Rolling Stone.

The introduction in 2009 of the anti-homosexual bill followed a conference in Kampala attended by American activists who consider same-gender relationships sinful, and believe gays and lesbians can become heterosexual through prayer and counseling. Some gay Ugandans still resent that American intervention.

"David's death is a result of the hatred planted in Uganda by U.S evangelicals in 2009," said Val Kalende, a Ugandan gay rights activist. "The Ugandan government and the so-called U.S evangelicals must take responsibility for David's blood."