A man and a woman were taken into custody.
Around noon Wednesday, officials said they were chasing the carjacked vehicle.
The men allowed the woman to take her 3-year-old daughter and 6-month-old son from the auto before they stole it, according to Capt. Bruce Fleshren. The chase crossed from IL into Missouri and then back into IL, according to St. Louis Police officials.
The St. Clair County Sheriff's Department was able to track the auto using its GPS system, and it was spotted by police on Interstate 70 in Glen Carbon just before noon Wednesday. IL authorities broke off their pursuit at that point. Police in Missouri tried to follow the vehicle, but lost it.
The suspects apparently got in a different vehicle, that of a family member who may not have known police were looking for them, authorities said. "It was fortunate that no one was injured, but these are very serious crimes that we want to get resolved as soon as possible", Captain Bruce Fleshren said in a press release.
A man and a woman have been arrested after being in possession of the stolen auto from this case. It happened just before midnight Tuesday in the 2600 block of Eastview Drive.
The St. Clair County Sheriff's Department said a 23-year-old had her 2009 Pontiac G8 with IL registration AP57112 taken from her at gunpoint by two men who blocked her vehicle in the 2600 block of Eastview Drive just before 11:30 p.m. Tuesday.
The sheriff's department described one of the suspect's vehicles as a gray or black newer Jeep Cherokee with Missouri plates.
The vehicles were last seen on Eastland Drive.
The two men took the woman's 2009 Silver Pontiac G6 at gunpoint, and Swansea reported a similar crime just 10 minutes before.