INTERVIEW Their mother is not a terrorist. Of that they are sure.

However, for the three sons of Bersih's chairperson Maria Chin Abdullah, the rest of the story on the arrest and detention of their mother has remained a mystery.

Denied access to their mother, who is being detained under the Special Offences (Security Measures) Act 2012, all they know now is that the time has come to continue the struggles of both their parents for free and fair elections.

Maria has been the face of Bersih for the coalition's last two rallies, but was prevented from leading the last Bersih 5 rally in Kuala Lumpur.

Maria's eldest son, Azumin Yunus, said they have been warned that she would one day be arrested for her work.

"But nobody ever expected her to be arrested and detained under Sosma.

"So, it is really a huge shock to all of us on that part. But we managed to cope," Azumin told Malaysiakini in a joint interview with his brothers on Monday night.

"We just told ourselves that, okay our mum is now detained, what can we do to help her?" said the 23-year-old who was at Dataran Merdeka for what would be the first of nightly vigils demanding Maria's release.

Azumin had earlier the same day lodged a police report against the conditions of Maria's detention, in solitary confinement at an undisclosed location.