TEMPE, Ariz. -- The city of Tempe is launching an investigation into whether the owners of a vacant lot at the intersection of Mill Avenue and Seventh Street violated city code with the placement and size of their "no parking" signs.

The situation came to light after an incident earlier this week in which more than a half-dozen people had their cars towed from the lot.

“The first thing (I thought) was ‘You’ve got to be kidding me,’” said Jay Thompson, one of the people whose car was towed. “And then I got angry because I didn’t know that I couldn’t park there.”

There are multiple signs at the lot warning drivers that they will be towed if they park in the lot. However, according to Thompson, they are hidden and do not follow city code.

One of the signs was located near the entrance to the lot on the back side of an electrical box. It was not visible as you drive into the lot.

Section 32-6 of the Tempe City Code also requires that the sign be 18 inches by 12 inches.

Thompson measured the sign -- which has since been removed -- and said it was not that large. An examination of the sticker mark left behind on the electrical box confirmed Thompson’s assessment.

Another sign located in the back of the lot does meet the size requirements, but is no more than two to three feet off the ground. According to city code, the signs must be mounted at least five feet off the ground.

“This signage is supposed to meet all these regulations, and it didn’t,” Thompson said.

“Was someone intending to scam people?” asked Steve Belt, whose car was also towed.

According to Onnie Shekerijan, a Tempe City Councilmember, the city has launched an investigation into whether Tempe Mill, the owner of the lot, violated city code with their signs.

Shekerijan, though, said, “It doesn’t matter to me if it meets the letter of the law. It doesn’t meet the spirit of the law.”

She believes that if private companies do not want people to park in their lots, they should make that very clear. She does not believe that happened in this particular case, calling the efforts of the owners of the lot “disingenuous.”

CBS 5 News contacted the attorney who represents the owners of the property Friday afternoon. The attorney was asked to forward the station’s contact information to the owners, but no phone calls have been returned.

The owners or managers of the property have added two signs to the lot, however, since Tuesday.

One sign is located at the entrance to the lot. It meets the requirements for size and height set forth by the city code.

The other sign is located approximately 100 feet behind the first sign and also follows city code.

Thompson and Belt both said that if those signs had been up on Tuesday, they would not have parked in the lot.

Shekerijan said she would suggest to other members of the council that they revisit the city code about towing in an attempt to further limit any “predatory” practices.