(CNN) An undocumented immigrant has admitted to killing a Reno, Nevada, couple using a gun he stole from their home, police say in a probable cause document.

President Donald Trump recently cited the killings and two others in a tweet in support of building a wall on the southern US border.

"Four people in Nevada viciously robbed and killed by an illegal immigrant who should not have been in our Country," the President tweeted Monday. "We need a powerful Wall!"

Four people in Nevada viciously robbed and killed by an illegal immigrant who should not have been in our Country. 26 people killed on the Border in a drug and gang related fight. Two large Caravans from Honduras broke into Mexico and are headed our way. We need a powerful Wall! — Donald J. Trump (@realDonaldTrump) January 21, 2019

The four people referenced include the Reno couple, plus two women who police say were victims of homicide in nearby Douglas County.

Connie Koontz, 56, was found dead January 10 in her home, and Sophia Renken, 74, was discovered dead January 13, also in her home.

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