Two people who were inside the home managed to flee the residence and inform police the man had made threats towards them.
An emergency situation was declared at 2pm and was revoked more than three hours later at 5.25pm after officers found the man dead inside the home. Ethical Standards Command will overview an investigation into the incident.
The two people managed to leave the property at 12pm and called police, letting them them know the man was armed with a firearm.
An emergency situation was declared just before 2pm.
Negotiators were on scene, along with other specialist police.
An exclusion zone has been set up, and covers the area within Tyberry Street, Tollett Street, Old Cleveland Road and Tinchborne Street.
Police have asked members of the public to avoid the area.