Police are trying to establish whether an alert was issued before an attack in Tarbaj, in which eight policemen were killed. Sources said there were signs of an imminent Al-Shabaab attack, considering an exodus by residents.
"The indications were there because, among others, elderly people had been moved from the area to Garissa and a number of youths had not returned to the area. Al-Shabaab militants were also sighted there,” said an official based in the area.