“After being kept in solitary detention for attitudinal adjustment, he showed signs of stress,” an informed source said. “When we let him out, he has kept quiet and does not try to mess with others. His behaviour is much better than when he was first sent in.”

The minor, identified only as ‘Moo Yong’, was arrested late last month for allegedly killing a person he robbed on April 26 in Chaiyaphum province.

Further investigation revealed this suspect, aged 17.5 years, was also accused of two other killings while robbing people in Buri Ram and Bangkok over the past three years.

Moo Yong showed no signs of repentance after being arrested.

The Chaiyaphum Provincial Youth Observation and Protection Centre believed it might not be able to control ‘Moo Yong’ and transferred him to a similar facility in Nakhon Ratchasima province, Muang Chaiyaphum Police deputy superintendent Pol Lt Colonel Nattapon Kingchoke said.

But as soon as the teen went to the Nakhon Ratchasima Provincial Youth Observation and Protection Centre, he started acting like a troublemaker, officials said. So, they sought a further transfer.

“He kept quarrelling with young inmates at the centre and ignored wardens’ orders. So on May 1, the Nakhon Ratchasima Provincial Youth Observation and Protection Centre sought court permission to transfer him back to Chaiyaphum province. After looking into the case, the court agreed to have ‘Moo Yong’ detained in an adult prison,” Nattapon said.

Moo Yong was sent to Chaiyaphum Prison last Thursday.

If convicted of the three murders, he could face many years in jail.