A lost deer caught trying to bust into a Bronx senior citizen home Tuesday morning had to be euthanized hours later, officials said.

The deer was spotted looking for an open door at the Citadel Rehabilitation and Nursing center at Kingsbridge on Cannon Place near Giles Place in Kingsbridge about 8:45 a.m., authorities said.

An NYPD Emergency Services Unit team tranquilized the deer and handed it over to the citys Animal Care Center of NYC, cops said.

Nature meets NYC, Deputy Inspector Terence O’Toole, the commanding officer of the 50th Precinct, said in a tweet Tuesday. A deer tried to enter 3400 Cannon Place The deer has been contained and will be treated and evaluated.

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A spokeswoman for Animal Care Centers of NYC said the deer arrived with serious trauma.

As is protocol with injured deer, humane euthanasia was performed, the spokeswoman said.

Sources with knowledge of the case said the deer suffered from capture myopathy muscle damage caused by the stress of being corralled.