A video of Colonel Abdoulaye Ahmat Haroun shooting two young mechanics at point-blank range, killing one, triggered such fury online that the government slowed the country's internet last month, a measure slammed by rights groups.

When a court in the capital N'Djamena convicted and sentenced Haroun for the murder on Thursday, "youths and women faked a brawl" to help him escape, Justice Minister Djimet Arabi told AFP.

Five hours later, the colonel "was recaptured with five accomplices, hiding in a house," by police and troops, Arabi said.

The head of the Chadian Human Rights League, Maxvelt Loalngar, said the colonel's relatives, some of them carrying "military weapons," hauled the colonel out of the defendant's stand and took him away, calling the judge a "slave" as they left.

The video of the colonel shooting the engineers circulated widely online, with some pointing to his ethnic background -- he is from the same community as President Idriss Deby Itno, who has ruled Chad with an iron fist for three decades.

Others said the colonel had acted with "impunity".

The furore was such that the government cut back on the speed of the internet in early August to slow the spread of messages "inciting hate" on social media.

The government said the measure was temporary, but it has not yet been lifted.

Deby last month slammed what he called the divisive use of WhatsApp and virtual private networks (VPN), both of which bypass public networks.

"WhatsApp and VPN were not created to insult one another, sow national division or criticise ethnic groups," he said, without specifically mentioning Haroun murdering the mechanic.

The colonel nearly escaped once before -- on August 9 he boarded a plane bound for Egypt, forcing Chad to order the plane to return to N'Djamena, where he was arresting on landing.