A top aide to a Republican state lawmaker in Maryland was charged Thursday with violating election law in connection with a deceptive robo-call that accused a GOP rival of supporting transgender rights.

Tyler Walch, who had been chief of staff to Del. Richard K. Impallaria (R-Harford County), could face one year in jail or fines of up to $1,000 for improperly concealing the party responsible for the robo-call targeting Del. Kathy Szeliga (R-Baltimore County), the House minority whip.

The Democratic-majority General Assembly dismissed Walch, who officially worked for the legislature, after the charges were made public, Impallaria said. Walch did not return messages Thursday seeking comment.

Prosecutor Emmet Davitt said Walch — who worked on Impallaria’s 2018 campaign — orchestrated a June 25 call, purportedly from the “national Center for Transgender Equality,” that reached more than 9,000 district residents and asked them to support Szeliga.

The robo-caller, named “Ali,” told listeners that Szeliga was “a true friend of the transgender community” and supported 2016 legislation “making it illegal to discriminate against Transgendered persons in the workplace,” Davitt said in charging papers. Soon, the caller predicted, lawmakers like Szeliga would help enact laws permitting transgender people to “use the bathrooms of their choice.”

Szeliga, who ran unsuccessfully for U.S. Senate in 2016, has never authored or supported legislation related to bathroom usage. She initially voted against an equal pay measure that included “gender identity” as one of the categories of people protected from discrimination. But she changed her vote to support an amended version of the bill, which became law.

Impallaria, who describes himself as a staunch conservative, and Szeliga were among 12 Republicans competing for their party’s nominations in the three-delegate legislative district that straddles Baltimore and Harford counties. Both won the June primary and were reelected in November.

During the nominating contest, Impallaria criticized Szeliga as a “Democrat in disguise.” They traded accusations of authoring attack ads, generating nasty campaign literature and backing competing political action committees responsible for the negative tone.

“It was probably the dirtiest campaign I ever saw,” said Impallaria, who questioned Davitt’s decision to criminally charge Walch for an “authority-line” violation — failing to identify who paid for the robo-call.

Such notification requirements are intended to help voters judge the veracity of the information they receive. But Impallaria, who described Walch as “a disabled American veteran who was honorably discharged and came to work for me after he left the service” compared the violation to “not dotting an ‘i’ and crossing a ‘t’. ”

Szeliga said that “willfully and knowingly misleading voters is shameful and wrong.”

“If you have something to say, and you believe what you’re saying, you should put your name on it,” she said.

Walch is scheduled for trial in Baltimore County District Court in March.

Prosecutors said he had shared the recording’s content with Impallaria, who was not charged in connection with the incident.