ZURICH (Reuters) - Former Gambian interior minister Ousman Sonko will remain in a Swiss jail for another three months after the country’s attorney general (AG) broadened an investigation into whether he committed crimes against humanity.

Sonko has been in pre-trial custody since January after the Geneva-based legal group Trial International filed a criminal complaint accusing him of having personally taken part in torture.

The attorney general’s office said it had since expanded its probe beyond the original allegations after hearing testimony from witnesses and after additional complaints were lodged against Sonko.

Sonko was interior minister from 2006 to 2016, when he fled to Sweden and thence to Switzerland, where he applied for asylum in November and was taken into police custody in January.

He served under authoritarian leader Yahya Jammeh, who fled into exile after losing an election to Adama Barrow in December. Jammeh has denied allegations of torture and killing opponents during his 22 years in power.

Barrow’s government is in contact with Swiss authorities following Switzerland’s request for legal assistance on Sonko’s case, the AG’s office said.

Sonko’s lawyer in Switzerland, Phillippe Currat, did not immediately respond to e-mail from Reuters seeking comment on Thursday morning.