Police are investigating a St. Paul home invasion robbery during which the suspect held a 15-year-old boy and his 27-year-old sister at gunpoint Thursday night.

Investigators are looking into whether the case is connected to a series of similar robberies on the East Side in February, said Steve Linders, a St. Paul police spokesman.

On Thursday at about 10:30 p.m., two people called 911 to report a burglary in progress on Iowa Avenue at Flandrau Street. One caller said an unknown male with a handgun was in the house. The other reported she locked herself in the bathroom and that her two brothers were also in the home.

Police arrived and set up a perimeter but did not find the suspect.

The 27-year-old had awakened to a man she didn’t know in her room, along with her 15-year-old brother. The suspect was pointing a gun at the teen and then pointed it at her, demanded money and told her it wasn’t a joke, according to Linders.

The woman handed the man a money jar, which contained $205. The boy bolted toward the basement and the suspect ran after him, according to Linders. Meanwhile, the woman grabbed her cellphone and locked herself in the bathroom to call police.

The teen found his brother in the basement and the two also locked themselves in a bathroom and called 911. The suspect didn’t go into the basement and instead left with the cash.

There did not appear to be forced entry to the home, Linders said.

The victims’ parents had left about 9:30 p.m. and returned home when they received a call about what happened.

The suspect is described as a light-skinned black male, 5 feet 10 inches tall, with a medium build. He was wearing black pants, black boots, a face mask and a black baseball cap. He was wearing a hooded shirt that one victim described as black and green, and the other said was dark colored.

Police ask anyone with information to call them at 651-266-5650.

The other armed home invasion robberies that police have been investigating occurred Feb. 22 about 2:40 a.m. on Maryland Avenue near Mendota Street; Feb. 16 about 7 p.m. on Fourth Street near Ruth Street; and Feb. 11 about 6:45 p.m. on Hazel Street near Arlington Avenue.

In one case, a 62-year-old man was briefly tied up, and in another children were threatened.