Attack on Colombia candidate highlights risks to left

Leftist presidential candidate Aida Avella, 65, a contender from the Patriotic Union party, gestures during an interview with Reuters in Bogota February 25, 2014. REUTERS/ John Vizcaino

BOGOTA (Reuters) - Through the noise and dust churned up by her armoured car, leftist presidential candidate Aida Avella assumed the popping noise was a rock hitting the wheel.

When her bodyguards lost radio contact with the rest of her security detail travelling behind, she knew something was wrong.