A Baton Rouge teenager arrested Friday in the January shooting death of another teen was also accused in a string of other crimes that occurred over the last few months — including intentionally starving his dog to death and convincing a teenage boy to shoot at a man walking home from work.

In two of the four crimes, police developed Sidney Ellois III, 18, as a suspect through his Instagram account, according to the warrants for his arrest.

Authorities on Friday arrested Ellois in the shooting death of Calvin Smith, 19, who was found Jan. 11 unresponsive and with multiple gunshot wounds in the parking lot of Carlins Food Mart on Plank Road.

Smith’s brother, Keon Preston, a chaplain with the Stop the Violence, a Baton Rouge nonprofit group, said Sunday he was relieved that Ellois is now behind bars.

“But at the end of the day there are two mothers grieving,” Preston said. “One is my mom … and the other is his. He made some poor choices and now he has to deal with the consequences.”

By the time U.S. Marshals found Ellois in a Wilmont Street home and arrested him, he was wanted in several other crimes, according to the warrants.

In late September, Ellois acted as a “lookout” while another man armed with a gun robbed a woman of her purse, which contained $2,900, according to an arrest warrant.

The victim told police she found a photo of Ellois and the other man on Instagram, an online mobile photo-sharing, video-sharing and social networking site. The two were holding a large amount of money — roughly the same amount that was missing from her purse — and the photo was posted after the robbery took place, the warrant says.

Then in a second incident just over a month later, Ellois convinced a 16-year-old boy on Oct. 28 to shoot at a man walking on North Acadian Thruway, according to an arrest warrant.

In that incident, Ellois and the teenager began following the man as he walked home from work, the warrant says. When the man noticed he was being followed and began looking over his shoulder, Ellois shouted, “What … you looking at? I will make my boy burn you,” the warrant says.

The tension escalated and Ellois began running at the victim as he ordered the 16-year-old to “burn him.” The teenager opened fire, an the man escaped unharmed, said Cpl. L’Jean McKneely, a Baton Rouge Police spokesman.

But in that incident, again, the victim found Ellois on Instagram and referred police to the account, which helped officers identify him as a suspect.

In the third incident, police found Calvin Smith unresponsive Jan. 11 in the parking lot outside Carlins Food Mart. A witness told police that Ellois and another man approached Smith in the parking lot and Ellois fired several shots, the warrant says. The report does not identify the other assailant.

In the fourth incident, Ellois was accused of animal cruelty when law enforcement went to his house on Duke Street off Plank Road on Jan. 22 to arrest him. Though Ellois was not there, officers found a chained dead dog underneath the house, that died a “tortuous death” of malnutrition, the affidavit says. Officers believe Ellois starved the dog to death on purpose, McKneely said.

Ellois was arrested Friday for his role in the four incidents when U.S. Marshals found him in the bedroom of a house on Wilmont Street, a police report said. Also in that bedroom was a .380-caliber handgun tucked underneath a mattress. The gun had been reported stolen in Jefferson Parish.

“We are at peace now, but we’re not peaceful,” said Preston, the chaplain with Stop the Violence. “At the end of the day, my little brother is still dead. We can’t bring him back.”

“All I can do is continue to pray for my family, and I’ll pray for his,” Preston said.

The reports do not say whether Ellois’ alleged conspirators have been arrested, including the 16-year-old boy who fired gunshots at the passerby or the man accused of robbing a woman at gunpoint.

Ellois, whose most recent address is listed as 3049 Iroquois St., was booked into East Baton Rouge Parish Prison on the following counts: second-degree murder, principal to attempted second-degree murder, aggravated cruelty to animals, armed robbery, illegal possession of a stolen firearm and contributing to the delinquency of a juvenile. He remains in jail with his bail set at $241,000.

Follow Daniel Bethencourt on Twitter: @_dbethencourt.