The father of fired National Security Advisor General H.R. McMaster has died under 'suspicious circumstances' at a nursing home in Pennsylvania.

H.R. McMaster, Sr died on April 13 at the Cathedral Village in the 600 E block of Cathedral Road in Roxborough.

He was receiving care there after he suffered a stroke, according to ABC 6. McMaster reportedly fell and hit his head. He was put in a chair and then died.

H.R. McMaster, Sr, the father of fired National Security Advisor General H.R. McMaster (pictured) has died under 'suspicious circumstances' at a nursing home in Pennsylvania. He was 84

McMaster, Sr died on April 13 at the Cathedral Village (pictured) in the 600 E block of Cathedral Road in Roxborough. He was receiving care there after he suffered a stroke. McMaster reportedly fell and hit his head. He was then put in a chair and then died

It was claimed that McMaster didn't receive the proper care, prompting the investigation.

Now, the Philadelphia police homicide unit, the district attorney, the Attorney General's office and the health department are investigating McMaster's death as 'suspicious'.

According to ABC, investigators are looking into information from staff members who informed the McMaster family that records were falsified pertaining to his death.

Philadelphia Police executed a search warrant at the facility Tuesday.

Cathedral Village told the station on Wednesday that they are fully cooperating with the agencies investigating McMaster's death.

They say they contacted the Department of Health the same day of his death and launched an internal investigation into the allegations that were made.

McMaster is the father of former National Security Advisor General H.R. McMaster (right) who was fired by President Donald Trump last month

A spokesperson said: 'We remain committed to the safety and welfare of all our residents and have made every effort to cooperate.'

McMaster Sr is the father of former National Security Advisor General H.R. McMaster who was fired by President Donald Trump last month.

Trump replaced McMaster with the current National Security Advisor John Bolton.

Bolton officially replaced McMaster on April 9.

A White House official said at the time that Trump and McMaster 'mutually agreed' that he would 'resign'.

'The two have been discussing this for some time,' the official added. 'The timeline was expedited as they both felt it was important to have the new team in place, instead of constant speculation.'

McMaster, a three-star Army general, said at the time that he will retire from the armed forces over the summer, passing up what was thought to be a chance to land a command position with a fourth star.