By Harmeet Kaur and Melissa Alonso, CNN

(CNN) -- A Black man is suing Galveston, Texas, and its police department for more than $1 million after a 2019 incident in which he was handcuffed and tied to officers on horseback as they led him down a street.

Donald Neely, 44, was arrested and charged with criminal trespass near a US Post Office in August of last year. Court records show the case against him was dismissed in March.

His arrest received national attention after photos showed two mounted officers from the Galveston Police Department leading Neely through the city by what appeared to be a rope. Police said at the time that the officer was holding a "line" clipped to Neely's handcuffs, not a rope -- though it's unclear what the difference is.

Critics and advocates said the photos conjured up images of the era of slavery, a point also made in the lawsuit filed by Houston-based attorney Julie Ketterman in Galveston County court on Wednesday.

"(Officers) knew or should have believed that Neely -- being a black man -- being led with a rope and by mounted officers down a city street as though he was a slave, would find this contact offensive," the lawsuit reads.

The lawsuit states that Neeley was humiliated as he was led down the street.

"Many individuals stopped, stared and asked questions. Neely felt as though he was put on display as slaves once were," the lawsuit states.

CNN has reached out to Ketterman for comment.

City has since stopped using technique for transport

The lawsuit claims that the officers injured Neely and caused him emotional distress. It also alleges that they acted maliciously and negligently while arresting him at a US Post Office. The lawsuit is seeking damages of more than $1 million.

Another attorney for Neely has previously said he has bipolar disorder and was homeless for several years. The Houston Chronicle reported that Neely eventually moved in with his sister and received medical treatment.

Donald Glywasky, the city attorney for Galveston, declined to comment, citing pending litigation.

CNN has also reached out to Galveston Police for comment.

The Galveston Police Department previously apologized for its treatment of Neely, with its police chief saying last year that the officers showed "poor judgment" and "could have waited for a transport unit at the location of the arrest."

The department said in the weeks following the incident that it had changed its policy to stop the technique of using mounted horses to transport a person during an arrest.

The city requested a third-party investigation of the incident, which was conducted by the Texas Rangers and determined that the arrest did not warrant a criminal investigation.

A separate county investigation examined the police department's policies, training and practices and was instructed to make recommendations on any changes that should be enacted.

The city released body camera footage after receiving the county's report, but it did not release the report's findings. The report was sent to the Galveston police chief to determine whether further action was needed, the city said last year.