On Sunday, a 77-year-old woman was robbed at gunpoint in her home, one day after an elderly couple was hospitalized following a home invasion robbery five blocks away.
The woman was not injured during the robbery in the 3700 block of N. Mayfield Avenue.
Police have not released the names of the robbery victims.
"The suspect entered her home, pointed a firearm at her, and demanded property," said San Bernardino police detective Tim Crocker. "She feared for her life and did everything the gunman said."
The suspect is a black male adult, about 5 foot 9 inches tall, thin build, with short hair and in his 20s, Crocker said.
On Saturday an 84-year-old woman was hospitalized after a man fitting the same description as Sunday's suspect beat her and her husband in their 40th Street home and fled with valuables and an antique pistol, relatives said.
"There are some similarities to these crimes," Crocker said, "but at this time there is nothing definitive connecting these two cases."
The 84-year-old woman remained hospitalized Thursday at Loma Linda University Medical Center, said sheriff's spokeswoman Cindy Bachman.
Her 95-year-old husband was treated and released the same day.
In November, not far from Saturday's and Sunday's robberies, an elderly woman was robbed and killed in her home.
Mary Beth Blaskey, 76, was found dead in her ransacked Fremontia Drive home.
Her 2001 Lexus ES300 was missing, but police later found the vehicle abandoned on the northeast end of town.
Blaskey's case is one of three involving elderly victims which led police to offer a $30,000 reward for information leading to arrests.
San Bernardino police Lt. Paul Williams said he believes investigators will be talking to the Sheriff's Department to look at similarities in the cases.
The San Bernardino Police Department is asking for anyone with information to please call Detective Thompson at 909-384-5668 or contact Sergeant Crocker at 909-384-5613.
Staff Writer Melissa Pinion-Whitt contributed to this report.