ST. LOUIS • Several young teenagers have been taken into custody for three attacks in downtown St. Louis in recent weeks, prompting officials to bolster patrols in the heart of the city.

Three girls, including a pregnant 13-year-old, were arrested in two attacks last month, and a boy was arrested in an attack earlier this week.

Capt. Daniel Howard, the commander of downtown’s District 4 police unit, said the attack on Monday and the earlier attacks are unrelated.

“They are only connected because they are so egregious and it is surprising to see young people acting this way,” Howard said. “They are both violent and disgusting.”

Police confirmed the arrest of the teenage boy Thursday, saying they believe he was the ringleader in an attack on a lawyer in a well-trafficked stretch of downtown on Monday evening.

Police say a 32-year-old man was walking home from work about 5 p.m. when he was surrounded by a group of teenage boys wearing khaki pants and black or navy blue shirts. The teens knocked the man out after asking him for money, according to police. The group took the man’s cellphone and money from his pocket and ran away.

The incident happened in the heart of downtown at North 10th Street, between Locust and Olive streets.

“We feel like we have the main aggressor,” Howard said.

The victim received numerous head and facial injuries, including broken eye sockets and teeth.

Howard said police are still putting their case together. He said he was unable to provide more details about the alleged assailant because it is a juvenile case.

Howard said the teens are students at a charter school near downtown.

Monday’s beating came about a week after two women were beaten by a group of girls in two incidents in the same general area.

One woman, 22, was carrying her groceries home when she was attacked by four girls ranging in age from 12 to 14 in the 1200 block of Washington Avenue about 6:50 p.m. on Oct. 25.

“The victim was walking west on Washington when four females approached her and one of the suspects punched her in the face,” according to a St. Louis police incident report. “The other suspects then took her cellphone and attempted to grab her groceries. While (she was) on the ground, the suspects also kicked the victim. The victim screamed and a nearby witness came to help her, causing the suspects to flee east on Washington.”

About 10 minutes later, the same group of girls targeted a 29-year-old woman in the 1000 block of Pine Street, according to police.

“The victim stated ... a group of four females approached her, took her purse and punched her in the face,” the incident report stated. “The victim fell to the ground and the suspects continued to kick her. The group then fled the scene, east on Pine. An area officer saw the females, and observed that they matched the description of the suspects responsible for the (other) incident.”

Police arrested three girls — 12, 13, and 14. They were taken to the juvenile detention center. The fourth girl was able to evade police.

Jeff Rainford, the chief of staff to Mayor Francis Slay, said the administration is monitoring the situation closely.

Police said on Thursday they have stepped up patrols and taken other precautionary measures downtown.