The INEM helicopter went missing in a mountainous area after dropping off a patient suffering from cardiac problems.

A medical helicopter has crashed in a mountainous area near Porto, Portugal‘s second biggest city, with all four onboard dead, local media and the country’s INEM emergency service reported.

State broadcaster RTP and daily Correio de Manha reported the helicopter had crashed on Saturday, killing two pilots, a paramedic and a doctor on board. The helicopter was found in the Salto area.

The INEM helicopter went missing at around 6:30 GMT on Saturday after dropping off a 76-year-old patient suffering from cardiac problems at a hospital in Porto.

According to INEM, the helicopter was on its way back to its base in the district of Braganca when it crashed in bad weather.

The helicopter was an Agusta A109S, operated by the company Babcock.

“The INEM medical emergency helicopter was built in 1997 and has since carried out the transport of 16,370 urgent patients, without [registering] any serious incident,” INEM wrote on its website.