[Updated 12:56 p.m] Sheriff’s officials are asking La Cañada residents to keep their windows and doors locked, after a home invasion robbery and the burglary of a neighboring home Thursday night have police on the lookout for two suspects armed with a handgun.

Those two crimes, along with another home invasion that occurred Wednesday night in La Crescenta, are being investigated by the Los Angeles County Sheriff’s Major Crimes Division, police said Friday.

On Thursday night, two elderly La Cañada residents were held captive during a home invasion in the 5100 block of Jarvis Avenue by two suspects who allegedly tied them up and robbed them before fleeing the scene, according to the Los Angeles County Sheriff’s Department.

A call came into the Crescenta Valley Sheriff’s Station Thursday at 10 p.m., though officials could not say who placed the call.

The suspects, described as two black men in their 20s, confronted the Upper Alta Canyada area homeowners, demanding money and property, according to a statement issued Friday by the Sheriff’s Headquarters Bureau.

“The suspects fled the location with miscellaneous valuables, leaving the victims unharmed,” the release stated.

While officers were on scene at the Jarvis Avenue home Thursday night, they were approached by a man who said his residence — located in the 1700 block of neighboring Earlmont Avenue — had been burglarized sometime between 7 p.m. and 10 p.m. that same night, Sgt. Booker Hollis of the Crescenta Valley Sheriff’s Station said Friday.

“He saw us there, not at his house, but at the robbery, and he notified us his home had been ransacked,” Hollis said. “A high amount of cash was taken and quite a bit of jewelry as well,” he said.

The estimated value of the jewelry taken from the Earlmont home was around $50,000, Hollis said.  The point of entry was determined to be an unlocked window.

Details of the Jarvis home invasion case, including a description of the two suspects, were similar to another armed home invasion that occurred Wednesday night in La Crescenta, in the 2900 block of Los Olivos Lane, at approximately 10:30 p.m., according to Lt. Elisabeth Sachs, day shift watch commander at the Crescenta Valley Sheriff’s Station.

In that incident, a man awoke to find two men in the process of tying him up, Sachs said. The men were in possession of a handgun. Once he was bound, the suspects took turns holding him at gunpoint as they robbed him of cash, jewelry and other items.

“One would hold him at gunpoint, while the other would ransack the house,” Sachs explained.

Once they left the house, the still-bound but uninjured man ran to a nearby residence for help.

When the homeowners saw him, they notified police, thinking he was trespassing.

One suspect was listed as being 6'3" and weighing about 200 pounds, while the other was described as a man of medium build. Both were wearing dark clothing, though some reports have stated they were wearing hooded sweatshirts.

The sheriff’s Major Crimes Bureau took charge of the investigation the morning after the La Crescenta burglary. The department handles cases thought to be part of a larger crime pattern throughout the county.

Calls made Friday morning to the officer leading the investigation were not returned. Hollis said investigators were still trying to determine if Thursday’s crimes are connected.

“Because of the close proximity to both, we just can’t discount it,” he said.

Although details on the means by which the robbers entered the Jarvis Avenue home could not be divulged, Sachs advised local residents to take precaution in securing their homes.

“We have such a sense of security in this community, but people have to keep their doors and windows locked,” she said. “It doesn’t matter where you live, you just have to take the precaution.”

--Sara Cardine, sara.cardine@latimes.com

Follow on Twitter: @SaraCardine.

Mark Kellam contributed to this report.

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