ALAMEDA -- An 83-year-old woman discovered a burglar inside her home on Adams Street on Friday afternoon, less than 24 hours after another elderly woman heard someone kicking in her front door as she sat in her living room on Otis Drive, police said.

The women were not hurt during the incidents, which come as police are urging people to make sure their homes are secure as they investigate a string of recent burglaries in the city.

Nine burglaries have been reported since April 15, with five taking place in the Otis Drive neighborhood between Fair Oaks Avenue and Willow Street, police said. Most of the cases have occurred during day time, when residents are at work or school.

The woman in the 3200 block of Adams Street discovered the man standing in her living room about 3:20 p.m. Friday as she was exiting her kitchen. Her 83-year-old husband had left the home minutes earlier to walk their dog.

"She came out and found this guy standing in her living room," Alameda police Lt. Ted Horlbeck said. "The front door was ajar. He tells her that he's there to help out with the gardening, but he quickly leaves. "

The woman described the suspect as black man about 45 years old, 6 feet 1 inches tall, 160 pounds and wearing all dark clothing. Investigators suspect the man, who fled in a black BMW, may have noticed the woman's husband leaving with the dog and thought no one was home.

The previous evening, an 84-year-old woman in the 1000 block of Otis Drive told police that she heard someone kicking in her front door about 8:30 p.m. as she sat in her living room. The man ran off when she began yelling.

The woman told police she did not get a good look at the suspect, describing him as a white man between 20 and 30 years old with short dark hair, a slender build and wearing dark clothing.

Minutes after the woman's 911 call, patrol officers detained a man who matched the description at Grand Street and Otis Drive. While the woman could not positively identify him as the suspect, officers still arrested him because they said he was evasive about his background as a parolee, Horlbeck said. The man was also allegedly carrying a credit card with the holder's name scratched off, as well as other items in various names, which the officers considered suspicious.

The same evening a burglary was reported shortly before 9 p.m. in the 1900 block of Otis Drive -- just blocks from the woman's home -- where among the items stolen was a resident's credit card that someone later used in Oakland, police said.

Other burglaries have taken place in the 1100 block of Willow Street, the 1000 block of Park Avenue and the 1200 block of Caroline Street.

Investigators suspect two teenagers who were seen acting suspiciously near some of the locations may have carried out several of the recent break-ins, Horlbeck said.

Both are described as black and between 16 and 18 years old with thin builds and short hair. They stand between 5 feet 9 inches and 6 feet tall. They also may be using a white or silver sedan that is possibly a Honda, according to witnesses.

Among the steps that police recommend people take to help prevent burglaries are making sure their doors and windows are securely locked, installing an alarm and sensor-activated lighting, and trimming bushes from near windows where someone could hide.

Alameda police ask people to immediately report any suspicious activity by calling 911.

Reach Peter Hegarty at 510-748-1654 or follow him on Twitter.com/Peter_Hegarty.