Police in Ireland are said to be baffled over news that two brothers walked free from a notorious Venezuelan prison, where they were serving an 11-year prison sentence for drug offences.

The Sunday Independent reports that sources within the Irish police say they have not heard from Venezuelan authorities since Leigh, 25, and Dermot O'Neill, 21, escaped in recent weeks.

A source told the newspaper: "Usually in cases like this there would be queries raised through diplomatic channels but in this case, no queries have been raised with us at all."

The two men from Athlone, Co. Westmeath are serving a prison sentence for drug smuggling after the Irishman they were travelling with died having swallowed a cocaine-filled condom.

Reportedly after they walked free from San Juan prison in the Venezuelan capital Caracas they phoned an Irish priest in Caracas, who used to visit them.

Police detained the two Irish men in March 2012 after their friend Martin Beirne died in a hotel room in Caracas after swallowing the class A drugs he intended to smuggle out of the country.

The two brothers were later detained by police at the offices of the Irish consulate in nearby Avenida de Mexico. Eldest brother Leigh later passed 92 balloons filled with cocaine. An X-ray of younger brother Dermot showed he had not swallowed any drugs. Leigh pleaded guilty to the smuggling charges, but younger brother Dermot insisted he was innocent. Both men received 11-year jail sentences.

Last week locals in Athlone told the Evening Herald the two men had been seen around the town.

"We never heard they were home so it was a bit of a surprise really," said one resident.  

"It's been on the radio here this morning and everything. It'll be the talk of the town in no time," she added.  

"We don't know if they got out themselves or were let out to be honest, but they're  home anyway, that's for sure.” 

Brothers Leigh, left, and Dermot O'NeillHandout