A Los Angeles Superior Court judge Monday dismissed all but one charge, felony poisoning, against a man accused of trying to slip a drug into a woman’s drink at a Santa Monica hotel bar.

Los Angeles Superior Court Judge Upinder S. Kalra dismissed 18 counts against Michael Roe Chien Hsu, having granted a defense motion to quash a warrant and suppress evidence stemming from that warrant in December.

Following a preliminary hearing Monday, Kalra ordered Hsu to stand trial on the remaining count. Arraignment was set for March 13.

Defense attorney Joshua Ritter said the alleged victim did not testify at the preliminary hearing, calling her absence “unusual.” Instead a detective testified on her behalf.

Three women saw Hsu allegedly trying to spike the drink of his female companion while she was in a rest room at the Fig restaurant inside the Fairmont Miramar Hotel on Wilshire Boulevard, one of the three wrote in a Facebook posting.

“He pulled her glass toward him, kind of awkwardly, then he took out a little black vial,” according to her account on Facebook.

“He opened it up and dropped something in. Then he tried to play it cool, like checking his phone and hiding the vial in his hand and then trying to bring it back down slyly.”

The suspect’s companion was told about the alleged spiking, as was restaurant staff, who called police. The would-be victim allegedly told one of the witnesses that the suspect was one of her closest friends.

Surveillance footage captured Hsu pouring an unknown substance into the woman’s wine glass, according to a statement of probable cause filed by a Santa Monica police officer. Ritter said law enforcement officers overreached in seizing other evidence, a claim supported by the judge’s ruling.

Hsu was arrested by Santa Monica police May 26 and posted bond six days later, after his bail was cut from $1 million to $350,000.