Mogadishu - Abdi Ali is awakened by a text message alert asking for urgent help: Five militants on a civilian bus are on the way to Mogadishu.
A former al-Shabaab foot soldier, Ali has defected from the Islamic extremist group and now helps Somalia's intelligence agency hunt down militants. The job is dangerous: Ali's former militant colleagues now hope to kill him and other defectors like him.
Ali does a quick scan around his neighbourhood before scurrying along a dirt road and jumping into a car with tinted windows. The car drives to a government checkpoint where Ali helps soldiers search cars.
"We have moles reporting their activities in their ranks. They're coming," Ali says. Moments later he receives a second text message that says the militants have changed their route. Nearby his colleagues frisk a man for explosives or a gun. The suspect is arrested and driven away.
"They come through here and get arrested, but many slip through every day," Ali said. "The city has many entrances they can use."
Security services in Mogadishu have seen a new wave of defections from al-Shabaab, men who can provide valuable information or scouting services for the police, military and intelligence service.
Though some defectors have proved to be double agents who carry out close-range attacks, the government is still embracing defectors for the valuable insider information the honest ones bring.
Ali defected last year from al-Shabaab, an al-Qaeda-linked radical group that carried out the Westgate Mall attack in neighbouring Kenya in September. He sought asylum and proved useful in the government's spy agency as a knowledgeable former militant who could spot al-Shabaab fighters trying to blend in.
Each day Ali drives through Mogadishu, the Somali capital, in search of familiar faces.
The job is risky. Two bullets from an assassin's gun penetrated his thigh last year. He fired back at his attackers. Another attempt on his life was made in March this year, he said.
While defectors can be valuable assets, they can be dangerous, too. Last year two al-Shabaab infiltrators carried out two suicide attacks against government installations.
One of the bombers, who had been a trusted soldier, blew himself up at the gate of Somalia's presidential palace, killing two people. The other infiltrator targeted a military camp in the capital, killing himself and one soldier.
A well-trusted defector who joined Somalia's intelligence agency shot dead a senior police commander earlier this year and re-joined al-Shabaab.
"They are not easily trusted and integrated into the army," says Abdirahman Omar Osman, the spokesperson of the Somali president. "Our policy is that they must go through a hard rehabilitation process, and after qualification, they work with our forces."
There's "no doubt" the defectors have been helpful to the security services, said Abdi Aynte, the director of Heritage Institute for Policy Studies in Mogadishu. "But there's an inherent risk in engaging them," he said. "Due diligence and stronger background checks are necessary to prevent infiltration."
Another defector, Yusuf Nor, said those suspicions mean that defectors are engaged in two simultaneous wars, against "al-Shabaab and mistrust."
Defections by the militant group's fighters have increased over the past two years following the ousting of the group's fighters from former strongholds. Government officials say an increase in defections has raised suspicions of planned infiltrations, forcing an increase in background checks.
"You never know. You can't judge them by their appearance or behaviour only," a senior Somali intelligence official, who insisted he not be named because of his work, said.
Despite the mistrust, the former militants can be great informants for security agencies struggling to stop a steady series of bomb and gunfire attacks, including major attacks on Mogadishu's courthouse and a United Nations compound this year.
Ali says he's being tracked by his government co-workers. He often fields calls from unknown persons asking him to return to al-Shabaab.
"They are [other] government spies checking my allegiance," he said. "How can I help those I am fighting? It'll take years to convince them."