Four people have been arrested on suspicion of involvement in the assassination of a senior Burundian army general earlier this week.

Attorney General, Valentin Bagorikunda, said on Friday that investigations were continuing to capture more suspects.

Brig.-Gen. Athanase Kararuza, a senior security adviser at the office of the first vice-president, was shot dead in the capital Bujumbura on Monday morning on his way to work.

Along with him in his car, his wife and one of his security guards were also killed on the spot and his daughter was injured and died on Thursday.

Bagorikunda said probes and court proceedings were also underway for suspects in the killings of other senior army officers in the past months.

Burundi has been in turmoil since April 2015 when President Pierre Nkurunziza announced he would seek a third term, which he later won.

His move sparked waves of protests and violence, in which more than 400 people have been reportedly killed.

Violence is again on the rise recently in the east African nation and mainly in the capital Bujumbura.