GARDNERVILLE RANCHOS, Nev. — The Latest on the killings of four people in Nevada over the past two weeks (all times local):

3:30 p.m.

Nevada resident Jim Gibson says he put his Gardnerville Ranchos home "pretty much on lockdown" following the murders of two women in his community, including his next-door neighbor, 74-year-old Sophia Renken.

Gibson said Wednesday that though authorities have arrested a man for the killings of the women and a couple in Reno, his neighborhood is still unnerved because police have released few details about the crimes, including a motive and information about how the suspect entered the homes.

Authorities say the 19-year-old man is believed to be in the U.S. illegally. President Donald Trump has cited the killings while making his case for a U.S.-Mexico border wall.

Gibson say he installed seven new home security alarms, floodlights and a camera around his home. He says that though he carries a concealed weapon and is always armed, he didn't leave his home for five or six days after Renken's killing because he feared he would find an intruder when he returned.

He says he has no clue if Trump's wall is a good idea, but if the suspect "snuck across the border," it bolsters Trump's argument.

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12:35 p.m.

Some residents of a northern Nevada community are still uneasy despite an arrest in two killings that were linked to two other deaths about an hour north in Reno.

Michael Lucas is a neighbor and former co-worker of one of the victims and says friends living in his neighborhood in Gardnerville Ranchos would walk into each other's homes without knocking. He says few people used to turn on their lights at night and now every home is lit up.

Lucas said Wednesday that people are waiting to see the evidence and what police know about a 19-year-old man accused of killing two local women in separate attacks over the past two weeks.

Authorities allege Wilbur Martinez-Guzman also killed a couple a few days later in Reno and was in the U.S. illegally from El Salvador.

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11:45 a.m.

Prosecutors in two northern Nevada counties say they are preparing murder charges against a 19-year-old from El Salvador suspected of being in the U.S. illegally and killing four people over the last two weeks.

Douglas County District Attorney Mark Jackson said Wednesday that charges in the slayings could be filed this week against Wilbur Martinez-Guzman.

President Donald Trump has made the case part of the national immigration debate. He says it shows the need for his proposed U.S.-Mexico border wall.

Sheriff Ken Furlong in Carson City says authorities are retracing Martinez-Guzman's steps and trying to determine a motive for the shooting deaths of a Reno couple and two Gardnerville women.

Furlong says it hard for investigators to believe that a killer randomly picked victims whose bodies were found about 35 miles (56 kilometers) apart.

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10:15 p.m.

A Nevada community shaken by the fatal shootings of four people over the past two weeks is grateful that the suspect is behind bars, but a motive for the crimes remains unknown.

The case has been thrust into the immigration debate, with President Donald Trumpseizing on the killings as evidence of the need for his proposed U.S.-Mexico border wall.

Authorities say the suspect, Wilbur Ernesto Martinez-Guzman, is a 19-year-old man from El Salvador who is in the U.S. illegally.

He's jailed in Carson City following his arrest Saturday on stolen property, burglary and immigration charges. He's due in court on those charges Thursday.

Prosecutors say they expect to file murder charges against him in the shooting deaths of a Washoe County couple and two women in Douglas County.