Mukono, Uganda (CNN) -- A pastor rebuked homosexuals at the funeral of a Ugandan gay rights activist, prompting chaos as sympathizers stormed the pulpit and grabbed his microphone away.

David Kato, 46, a prominent rights campaigner in the east African nation, was beaten to death with a hammer this week in his house near the the capital, Kampala.

His name and photo were printed on the cover of a tabloid newspaper late last year that called for gays to be executed under a banner that read: "Hang them."

His funeral spiraled into chaos after the pastor denounced homosexuals, saying they "would go to hell."

Mayhem ensued as mourners took away the pastor's microphone and police whisked him away from the angry crowds. A sympathetic Anglican bishop stepped in and laid Kato to rest as hundreds gathered Friday in the small hillside village outside the capital, Kampala.

Mourners included embassy staff and diplomats from various countries, and members of the lesbian, gay, bisexual and transgender community.

Activists wore black T-shirts with Kato's picture on it and rainbow colored-flags associated with the gay pride.

Tears -- and tributes -- flowed as family members wailed while others collapsed. A statement was read from U.S. President Barack Obama, who condemned the killing and urged authorities to swiftly bring the perpetrators to justice.

Police have said initial investigations are focusing on robbery in Kato's rough Mukono neighborhood, but rights activists said he was a victim of homophobia.

One suspect -- Kato's driver -- has been arrested while another man is still at large, authorities said. The second suspect is an ex-convict who was staying with Kato before his death.

Human rights activist Naomi Ruzindana said the killing is not a robbery gone wrong.

"I don't think it's a coincidence that it happened ... he had got threats over and again," she said.

Earlier this year, Kato and two activists won a case against the magazine that published the list. The court ruled that media in Uganda are barred from releasing details of known or potential homosexuals in the country.

Homosexuality is illegal in most countries in Africa, where sodomy laws were introduced during colonialism. In Uganda, homosexual acts are punishable by 14 years to life in prison, according to rights activists.

Ugandan lawmakers shelved a controversial "anti-gay" proposal introduced in 2009 that would impose tough penalties against homosexuality -- including life imprisonment and the death penalty.