Kenyan court has found three men guilty of abetting al-Shabab fighters who carried out a university attack that killed 148 people, mostly students, four years ago.

The convicted face life sentences and will be sentenced on July 3, the first to face justice for the April 2, 2015 attack on Garissa University in northeast Kenya.

Judge Francis Andayi on Wednesday said the three- Kenyans Mohamed Ali Abikar, Hassan Aden Hassan and Rashid Charles Mberesero, a Tanzanian – “were members of the al-Shabab terrorist group whose members carried out the attack”.

Prosecutors had proven “beyond reasonable doubt” that they were involved in a conspiracy for “committing a terrorist act”, he said.

Defence counsel Mbugua Mureithi said he would appeal.

The court in the capital, Nairobi, acquitted a fourth person, Sahal Diriye Hussein. A fifth suspect was acquitted earlier this year.

Al Jazeeras Catherine Soi, reporting from Nairobi, said many Kenyans were following the case closely.

“It is [a very sensitive matter because it is] the conclusion of the first major case involving a big terrorism incident and it is going to set a precedent for other cases that are still in court.”

The attack was carried out by four gunmen from al-Shabab, a Somali armed group linked to al-Qaeda.

The attackers stormed the students hall of residence at dawn and opened fire indiscriminately, before freeing some Muslim students and then killing others identified as Christians. All four gunmen were later killed by security forces.

It was the second-bloodiest attack in Kenya s history, surpassed only by al-Qaedas bombing of the United States embassy in Nairobi in 1998 that killed 213 people.

The security response to Garissa was strongly criticised by many Kenyans. It took 16 hours for a special anti-terror unit to bring the attack to an end, their deployment slowed by a senior police officer who had commandeered the forces plane for a family excursion.

Al-Shabab attacks

During the trial, prosecutors placed 22 witnesses on the stand, most of them student survivors.

They also showed evidence that the three had been in contact with the gunmen, especially by telephone.

Mberesero, the Tanzanian, had been also been seen on the university campus three days before the attack, and on the day of the assault itself had been found under a bed in the hall of residence and was unable to explain why he was there, prosecutors said.

The three convictions are the first to result from a long-running investigation and prosecution.

All four gunmen were killed by security forces. The operations suspected ringleader, Mohamed Mohamud, was killed in southwestern Somalia in 2016. Al-Shabab said he had been killed by “US crusaders”.

The armed group was chased out of Somalias capital, Mogadishu, in 2011 by the 22,000-strong African Union peace-enforcement mission, AMISOM.

They nevertheless control vast rural areas and remain the key threat to peace in Somalia. The group is fighting to overthrow the internationally backed government in Mogadishu but also regularly carries out attacks in neighbouring Kenya, which has troops in Somalia as part of AMISOM.

In September 2013, it claimed responsibility for a dramatic raid on the Westgate shopping mall in Nairobi that killed 67 people over a four-day siege.

In June-July 2014, around 100 people were killed in raids in the coastal Lamu region in Kenyas northeast, home of a once-popular tourist island.

In January 2016, al-Shabab overran a Kenyan army outpost at El-Adde in southern Somalia. Some estimates say that as many as 180 soldiers died. And on January 15 this year, 21 people were killed and 28 wounded when five al-Shabab gunmen attacked the DusitD2 hotel and office complex in Nairobi.