"That is a very disturbing, very high number," said civil rights lawyer David Rudovsky, who has for decades taken the city to federal court over prison conditions.
Rudovsky said he would request the records on the four inmates. If the cases appear to be related to poor conditions for the inmates, Rudovsky said he would "consider going back to court" against the city.
Prison Commissioner Louis Giorla said in a statement that the three deaths do not appear to be related. The cases are being investigated by the prison system and by Philadelphia police.
Giorla said that "all corrections officers and support staff are being directed to be extra vigilant in their observation of and interactions with inmates.
"All inmates housed in the affected areas are being seen by behavioral health staff to assess their current mental state," Giorla said.
He also said that a regularly scheduled review by an independent prisons monitor of behavioral health services, set to begin Monday, will be devoted solely to the suicides.
Prison overcrowding has become a serious problem again. The prison system's total inmate population as of Friday was 8,727. It had dropped to 7,800 about 15 months ago, Rudovsky said.
Lawyers representing inmates say the spike in population comes as the number of prison staff has decreased, requiring more lockdowns to manage the inmates.
The lawyers also say medical care is lacking, especially for inmates with mental-health issues.
The Detention Center has no air-conditioning for the inmates or staff who oversee them.
Contact Robert Moran at 215-854-5983, or firstname.lastname@example.org, or follow @RobertMoran215 on Twitter.