YANGON (Reuters) - A prominent Myanmar Muslim lawyer assassinated in Yangon was being closely watched by intelligence agents, according to friends and colleagues, and had received past threats over his sensitive work as an adviser to Aung San Suu Kyi's ruling party.
People close to advocate Ko Ni, whose killing has been described by the government as an attempt to destabilize the country, say they warned him to take more precautions for his security, but he had brushed off their concerns.
"I always worried about my boss," said a staffer in Ko Ni's office, who spoke to Reuters anonymously because he feared repercussions. "I would follow behind him for security when he was walking home."
A lone gunman fatally shot Ko Ni in the head on Sunday as he held his young grandson at a taxi stand outside Yangon's international airport.
The killing of a lawyer known for his work on amending Myanmar's military-drafted constitution comes amid heightened communal and religious tensions in the Buddhist-majority country, and has raised the specter of political violence marring a widely lauded transition to democracy after decades of junta rule.
The motives of the gunman - who is in police custody - remain unclear, but he appears to have known Ko Ni's arrival time at the airport.
Police have said they believe a wider conspiracy led to the shooting, and a second suspect was arrested near the Myanmar-Thailand border on Monday, according to Kan Win, deputy chief of police in the border state of Kayin. The office of the civilian president said initial interrogation of the gunman "indicates the intention to destabilize the state".
Constitutional law expert Ko Ni, 63, was instrumental in carving out the position of "state counselor" for Nobel laureate Suu Kyi, whose National League for Democracy (NLD) party came to power in April.
The position allows her to effectively lead the government despite being barred from the presidency under the 2008 constitution because some of her family members are foreign nationals.
Ko Ni was working on amendments to the charter, which was drawn up by the generals that ruled the country and guarantees the army a quarter of parliamentary seats and control of security ministries, people who worked with Ko Ni told Reuters.
These colleagues say the veteran lawyer was working on other sensitive topics, too.
Ko Ni wanted to take military officials out of day-to-day administration, and was also spearheading an Interfaith Harmony Bill that would include measures to tackle hate speech, hate crimes and discrimination.
He wanted to amend a 1982 law that restricts citizenship for people not considered members of indigenous ethnicities - such as the 1.1 million Rohingya Muslims in the country's northwest.
After Buddhist nationalists forced the NLD to cancel a talk at which Ko Ni and another Muslim would be speaking, he said his closeness to Suu Kyi and his work on the constitution were especially sensitive.
"I am a targeted person," he told campaign group Fortify Rights in August 2015, according to a transcript reviewed by Reuters.
"I take care of myself and keep a low profile now. I only give training on the constitution and laws, and only indoors."
When Ko Ni began campaigning for the NLD ahead of a historic election in November 2015, he started receiving warnings he should stop his political work, said Ohn Hlaing, a lawyer at the Laurel Law Firm that Ko Ni founded.
"If he didn't listen, they would kill him. I didn't think it would happen," Ohn Hlaing told Reuters. He was not aware of any specific threats in recent weeks.
After the NLD came to power, safety concerns were coupled with signs of increased surveillance of Ko Ni by intelligence agents, according to three co-workers and two relatives.
Two of Ko Ni's associates told Reuters they were directly approached by agents to provide information about his activities.
Yin Nwe Khine, Ko Ni's daughter, said her father said little to his family about threats or surveillance.
"He told us he was being watched by someone, but we didn't know who," she said.
Aye Lar, an official with military security affairs in Botataung, the area of Yangon where Ko Ni lived, told Reuters he was charged with watching Ko Ni - which he characterized as routine surveillance of a prominent local figure.
An official at the Ministry of Defense's press bureau declined to comment.
Official monitoring of the population was widespread during military rule in Myanmar and the domestic intelligence agencies have not been disbanded.
"We had to report to above about Ko Ni's activities, like his meetings, where he went, and what did he did," said Aye Lar.
Myo Win, founder of Smile Education, a non-profit foundation, who worked with Ko Ni to promote tolerance between different faiths, said this surveillance followed Ko Ni when he traveled outside of Yangon, citing a trip to the northeastern city of Lashio in October during which intelligence officials visited Ko Ni's hotel.
But Ko Ni seemed unconcerned about being followed and about his own security, said Myo Win.
"He continued to take Yangon taxis everywhere," Myo Win said. "The NLD should have some security for their important people".
Additional reporting by Shwe Yee Saw Myint; Editing by Alex Richardson