Four men that escaped a psychiatric facility for convicts are suspected of taking a staff member hostage and inflicting physical injury to force him to let them out, German investigators said on Sunday.

The fugitives escaped the BKH Lerchenhaid hospital, which lies in the town of Straubingen in the southern German state of Bavaria, on Saturday.

What else do we know about the search for the fugitives?

On Sunday, a police spokesperson said that officers were still searching "intensively" for the four escapees.

Roughly 100 officers were involved in the search.

Police said in a statement the day after the breakout that the four men attacked the staff member, held him down and forced him to open the facility's gate, escaping shortly after 9 p.m. local time (1900 UTC).

The facility patients used both blunt and sharp objects in the attack, the police spokesperson said.

The worker sustained injuries to the face and has been hospitalized.

As part of search measures, police published photos of the four fugitives.

What do we know about the four men?

Among those who fled the facility were a 31-year-old Bosnian national, two 28-year-olds with German nationality and 27-year-old citizen of Kosovo.

The men were in custody at the facility over property and drug-related offenses.

Police said that the four men were to be considered dangerous and repeated previous warnings that members of the public should not pick up any hitchhikers or approach the fugitives.

The police statement said that anyone with information as to the whereabouts of the fugitives or who has seen any suspicious activity should call the 110 emergency number.

sdi/msh (dpa, AFP)