Police arrested one man and are searching for a second suspect in connection with at least two carjacking's and a robbery in the Streeterville neighborhood.

The couple were pulling out of a Streeterv

ille parking lot when a cargo van raced up to their black Jeep Cherokee and a gunman jumped out and yelled, "Get out of the car."

They were the first victims of what police say were at least two carjackings and an armed robbery committed by the same two men over the past week in the downtown neighborhood.  At least one suspect was in custody and police were searching for the second. No injuries were reported in any of the attacks.

The couple, both 31, had just gotten into the Jeep in the 400 block of North McClurg Court around 7:30 p.m. Saturday when a “dirty white or gray” van blocked them in, according to a police report.

A man holding a gun in his left hand got out of the van and rushed up to the driver’s window and ordered the couple out, the report said.

The woman ran and hid near an elevator, while the man took out his wallet and offered the gunman cash and credit cards, police said. The man then took several steps back and lay down on the ground, according to the police report.

The robber then got into the Jeep and, joined by another person, sped off, hitting a parking gate arm and damaging the Jeep’s driver’s side mirror.

Two days later, a 31-year-old man was carjacked by a gunman around 8:25 a.m. Monday in the 300 block of East Illinois Street, according to Police News Affairs Officer Stacey Cooper.  The man was in a 2007 Jeep Grand Cherokee when a man tapped on the window with a gun, forced the driver out and drove off.

The man had just gotten into the Jeep and was holding his cell phone and cash when the gunman, wearing a mask, approached and, according to the police report, said: “Get the f--- out of the truck. . .Give me your f------ truck. . .Give me everything you have.’’

The gunman took everything the man had in his hands, then pointed the handgun at the man forehead and hit him in the chest with the butt of the gun, according to a police report.

The robber told the man to run and he headed to a parking lot office attendant and asked him to call 911. The man then ran down the ramp of the parking lot and saw the robber -- without the mask -- driving his car through the gate of the lot and fleeing west on Grand Avenue, running a red light at Fairbanks, the report said.

The victim told police he believes the gunman tried to disguise his voice, the report said.

On Sunday, at about 9:20 a.m., a 39-year-old man was walking in the 500 block of North McClurg Court after parking his vehicle. A Jeep Cherokee pulled up and a man wearing dark clothing threatened him with a gun and took his belongings, Cooper said. The Jeep was not stolen but police believe the robbery was related to the carjackings.

In a separate incident, a gray 2014 Chevrolet Cruz was reported stolen Monday, although News Affairs did not have information on when the theft took place or how it was stolen. The alert, however, listed the theft of the Cruz among the “series” of carjackings.

News Affairs did not have information about the robbers’ descriptions.

On Tuesday, a 22-year-old man was arrested in the Gresham neighborhood and remained in custody Wednesday. No charges have been filed.

Tribune reporter Liam Ford contributed to this report.

lford@tribune.com | Twitter: @ltaford