(CNN) — New Zealand authorities are racing to identify the 50 people killed in a massacre at two mosques so that their families can bury them in accordance with Muslim tradition.

In addition to the people killed in the attack Friday, 50 were wounded in the shootings, authorities said. 

Islamic tradition calls for a person to be buried as soon as possible after death — ideally within 24 hours.

Prime Minister Jacinda Ardern said Sunday that authorities had started returning identified bodies to families, and all bodies will be returned by Wednesday.

Six disaster victim identification experts have traveled from Australia to help hasten the process, she said.

New Zealand police described efforts to identify the victims as “detailed and complex work” that must be completed thoroughly.

“It’s vital we have certainty around cause of death for any future court proceedings,” Detective Superintendent Peter Read said.

Chief Coroner Deborah Marshall addressed the difficulties faced by authorities in correctly identifying the bodies of the victims of Friday’s terror attack.

“There could be nothing worse than giving the wrong body to the wrong family,” Marshall said. “This is not going to happen here.”

Speaking at the same press conference, deputy police chief Wally Haumaha said that authorities are working closely with imams and the Federation of Islamic Associations of New Zealand.

“We acknowledge that the last 48 hours have been the most horrific in these families’ lives. We understand it is an added trauma for them that they have not been able to bury their loved ones quickly, according to their religious duty,” said Deputy Commissioner Wally Haumaha.

“This is an unprecedented event and the support of the Muslim leaders and their community has been invaluable.”

Victims hailed from around the world. Nine Pakistanis were killed in the attack. Six of them will be buried in New Zealand, Pakistani Foreign Minister Shah Mehmood Qureshi told reporters Sunday.

Three bodies will be brought back to Pakistan to be buried, he said, adding that he has asked New Zealand to hasten return of the bodies.

Another Pakistani person remains hospitalized and in a critical condition, Qureshi added.

Makeshift memorials have sprung up around the mosques, with flowers and notes bearing messages of hope and love.

The victims’ names were not made public but a preliminary list has been shared with families, New Zealand Police Commissioner Mike Bush said Sunday.

Two days after the shootings, Brenton Harris Tarrant, 28, appears to be the only person in custody who has been linked to the attack.

Three other people who were initially detained were not involved in the attacks, Bush said, but authorities are not ruling out the possibility of other suspects.

“I will not be saying anything conclusive until we are absolutely convinced as to how many people were involved, but we hope to be able to give that advice over the next few days,” the police commissioner said.

British police arrested four over comments about the attack

Graphic video raises questions over offensive content Tarrant live-streamed the attack on Facebook and the graphic video was copied and reshared by users of the platform.

Facebook removed 1.5 million videos of the New Zealand mosque attack in the first 24 hours, the social media company tweeted Sunday.

Additionally, all edited versions of the video that don’t show the graphic content were also removed “out of respect for the people affected by this tragedy and the concerns of local authorities,” Mia Garlick, of Facebook New Zealand tweeted.

Tarrant also sent an 87-page manifesto to Ardern minutes before the attack began.

The document, also posted on social media before the shooting, was filled with anti-immigrant, anti-Muslim screeds. Authorities have declined to discuss potential motives for the attack.

Tarrant, who is facing one murder charge, made a hand gesture associated with white supremacists when he appeared in court Saturday.

He was remanded in custody and will reappear in court April 5.