Family of a Chadian military officer faked a fight and rushed him out of the court moments after he was sentenced to five years in jail for a murder that sparked nationwide outrage, the government said.

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

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

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 him 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 30 years.

Others said the colonel had acted with "impunity".

The government said slowing down the internet was temporary, but the measure has not yet been lifted.

Last month, President Deby 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 almost escaped once before: On August 9, he boarded a plane bound for Egypt, forcing Chad to order the plane to return to Ndjamena, where he was arrested on arrival.