AUSTIN — It's been three years since Texas Attorney General Ken Paxton was indicted for securities fraud, and his Democratic challenger marked the date — with cake.

Justin Nelson, a Houston attorney vying to strip the Republican incumbent of his title, released a YouTube video campaign ad on Thursday wishing Paxton, "Happy birthday to your criminal charges." The short video, which was recorded to appear like a baking tutorial, also criticizes Paxton for campaign contributions and an incident where he took — then returned — a local lawyer's $1,000 Montblanc pen.

"Poll results released this week show our campaign with a double-digit lead because Texans support Attorney General Paxton's leadership in fighting and winning for Texas, and they won't be distracted by juvenile, half-baked campaign stunts from a liberal trial lawyer," Matt Welch, Paxton campaign spokesman, said in an email.

In July 2015, the attorney general was indicted for three felonies: two first-degree charges of securities fraud and one third-degree charge for allegedly acting as an investment adviser representative without being registered with the state. Paxton has pleaded not guilty to all charges, which he says are politically motivated. If convicted, he could face up to 99 years in prison.

Paxton has not gone to trial. His case is on hold, and is likely to remain delayed until after the November election as the Texas Court of Criminal Appeals mulls a related lawsuit over the prosecutors' pay.

Paxton did not draw a Republican challenger in the GOP primary and has consistently out raised Nelson, besting him 3-to-1 in the most recent fundraising period. Nelson also trailed Paxton in a Texas Lyceum poll of likely voters released earlier this week, with 35 percent of those questioned saying they would vote for Paxton and 25 percent backing Nelson.

Without a large campaign fund for traditional media, Nelson has turned to YouTube to get his message out, releasing four videos in the last month. Welch said that the Paxton campaign plans to advertise through more traditional media, and Thursday posted its own YouTube ad based on Paxton's introduction at the Texas State GOP Convention in June.

Paxton's last YouTube campaign video was uploaded two months ago, soon after President Donald Trump endorsed Paxton for re-election.