Tens of thousands of people gathered in the Myanmar city of Yangon on Monday for the funeral of Ko Ni, a Muslim lawyer shot dead the previous day,

The 63-year-old was an expert in constitutional law and adviser to Aung San Suu Kyi's ruling National League for Democracy (NLD) party that came to power in April.

A prominent member of Myanmar's Muslim minority, the lawyer was involved in efforts to amend a military drafted constitution.

Police have arrested a 53-year-old man, suspected of being the lone gunman who shot Ko Ni in the head outside Yangon's international airport on Sunday evening.

Ko Ni had just embraced his young grandson as he stepped out of the airport terminal on his return from Jakarta, said the lawyer's daughter Yin Nwe Khine.

"My father was talking to his grandson. Then, I heard a gunshot. At first, I thought it was a car tyre blowing out, then I saw my father lying on the ground," she said.

The victim had just returned from a trip to Indonesia, where Myanmar government officials and Muslim community leaders discussed with Indonesian counterparts issues of reconciliation.

Taxi driver Nay Win, 42, was also killed when he attempted to apprehend the gunman, according to state media.

"We have detained and are questioning the gunman to find out why he killed him, and who is behind it or paid him to do it," Zaw Htay told Reuters news agency.

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An estimated 100,000 mourners, including family members, lawyers, NLD activists and members of Yangon's diplomatic corps attended Ko Ni's funeral at a Muslim cemetery in northern Yangon.

Aung San Suu Kyi was not in attendance and has yet to comment on the killing. Her party said on Sunday that Ko Ni's death was "a great loss for which there is no substitute".

The apparent assassination comes amid heightened tensions in Buddhist-majority Myanmar, where Aung San Suu Kyi is under pressure over a heavy-handed security operation in an area of the country's northwest that is populated mostly by Muslims.

Ko Ni, an expert in constitutional law, had spoken out about the powerful role the military retains in governing Myanmar, despite handing over power to Aung San Suu Kyi's civilian administration in April.

"My father was often threatened and we were warned to be careful, but my father didn't accept that easily. He always did what he thought was right," said Yin Nwe Khine.

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"A lot of people hate us because we have different religious beliefs, so I think that might be why it happened to him, but I don't know the reason."

Ko Ni had joined Pe Myint, the minister for Information, on the visit to Muslim-majority Indonesia, billed as an opportunity to share experiences of national reconciliation.

The delegation included several Myanmar Muslim leaders, some belonging to the mostly stateless Rohingya minority.

Yanghee Lee, the UN's special rapporteur for Myanmar, voiced her outrage over Ko Ni's killing, saying she had met him on her last trip to the country earlier this month, which included a visit to Rakhine.



"My deepest and most sincere condolences to the family of U Ko Ni the most prominent and respected Muslim lawyer of Myanmar," she tweeted, calling on Aung San Suu Kyi's government to "get to the bottom" of his death.