Four prison inmates tested positive for cocaine last week, shortly after one of them returned from prison leave, senior prison sources told Times of Malta.
They said the inmate managed to smuggle cocaine on his return to prison and then distributed it to the other three inmates.
Prison authorities ran drug tests when some officials suspected that the inmates were under the influence of drugs. Sources said other inmates were tested as well but only those four inmates' tests returned positive.
Disciplinary action has been taken against the inmates, the sources confirmed.
Questions sent to prison authorities have not yet been answered but, on Wednesday, Maltatoday reported that prison authorities said that no drugs were found on prison grounds and that this was an isolated case.
They said that out of the 721 drug tests that prison officials ran since January, only these four tested returned positive.
A hot potato
The issue of drugs inside prison has been a hot potato for decades. Former inmates say that for many years, drugs would seep into prison fairly easily, and drug dealing within prison walls was common. Some former prisoners even say that, at times, drugs were more accessible in prison than on the street.
That seemed to have come to a halt in 2018 when a former army pilot, Alex Dalli, took over prison and instituted a regime of zero-tolerance for illicit substances.
Inmates and officials alike admit that drugs truly and remarkably vanished from prison during his tenure, but the controversial boss also ran the prison with highly questionable tactics. After 14 inmates died on his watch in three years and an investigation called for an overhaul of the prison system, Dalli resigned.
Sources also say his successor, Robert Brincau, sustained the zero-tolerance policy successfully before having to step down earlier this year, and the young, new chief who took the seat just over two months ago is striving not to lose the streak.
Prison leave controversy
Prison leave has also recently become controversial after it was revealed that one of Daphne Caruana Galizia's convicted killers - George Degiorgio - was granted a few hours of prison leave to attend a family baptism party escorted by prison guards.
The law allows prison authorities to let inmates attend specific family events - like baptisms and marriages - for a maximum of 12 hours, but critics and Caruana Galizia's family argued Degiorgio should have never been allowed out, since he continues to face charges on other serious crimes and is said to have ties to criminal circles outside of prison.
Drugs in prison remain controversial since most inmates in Malta's prison are serving time for crimes related to drug abuse, trafficking, or for other crimes related to drug addiction, such as stealing with the intention to buy drugs to sustain the addiction.