Murder defendant was meeting Kristen Marti for paid sex

October 4, 2018

Robert Koehler

The man accused of murdering 26-year-old San Luis Obispo woman Kristen Marti was a john who was meeting the victim for paid sex on the day she disappeared, according to police testimony delivered Wednesday. [KSBY]

During a preliminary hearing in San Luis Obispo Superior Court, multiple San Luis Obispo Police Department officers testified about the investigation into Marti’s disappearance and murder. A forensic toxicologist also testified that there were drugs in Marti’s system at the time of her disappearance.

According to testimony from investigators, Marti was known to prostitute herself for sex and drugs. Defendant Robert Koehler was known to seek women for sex on Craigslist and Tinder, even when he had a pregnant wife.

Marti was last seen alive on Jan. 9 in the 1800 block of Perfumo Canyon in San Luis Obispo. Koehler is believed to have been the last person to have been with Marti while she was alive, and he reportedly told investigators that he spent time with the woman on Jan. 9.

The murder victim had been missing for nearly three months when officers found her body in a creek near Perfumo Canyon during a large search of the area. In early May, Koehler fled the Central Coast with his wife. Officers were tracking him, though, and he was arrested in Minnesota and extradited to San Luis Obispo County.

Koehler is charged with murder and accused of using a knife to slit Marti’s throat. He has pleaded not guilty.

During Wednesday’s preliminary hearing, Officer Greg Benson testified that Marti and her boyfriend Nick Reed lived on the street and in hotels and used heroin and methamphetamine.

On Jan. 9, Reed was aware Marti was going to meet up with someone in Pefumo Canyon, Detective Chris Chitty testified. Marti never called for a ride home, but she texted Reed in all capital letters, asking if he was on Perfumo Canyon.

Kristen Marti

Former police officer Jacob Dinsmore, who days later took a missing person report from Reed, testified Reed told him that he and another friend drove up to Perfumo Canyon and saw Marti with an unknown man inside a car. Reed told Dinsmore Marti appeared to be okay.

Police testified that Marti was using textPlus, an app that allows users to anonymously text and call, in order to communicate with a user by the name of John Hill. An IP address associated with the user’s email was traced to Koehler’s mother’s house, and investigators believe John Hill was Koehler’s username on textPlus.

Between Dec. 15 and Jan. 9, Marti and the user exchanged more than 100 text messages. The messages discussed exchanging drugs or sex for money. Various images were also sent in the messages, including one showing a man in a Mullahey Ford mechanic shirt with the name “Robert” on a patch.

Koehler was the owner of a mobile mechanic service that operated in northern Santa Barbara and southern San Luis Obispo counties prior to his arrest.

On Jan. 9, the textPlus user believed to be Koehler offered to pick up Marti in San Luis Obispo for paid sex. The man also asked if Marti wanted to do some “go fast,” a street term used for methamphetamine or cocaine.

Earlier in the day, Koehler met another woman for sex. The woman told police she believed Koehler was high, sweating profusely and seemed frustrated.

At about 7 p.m., Koehler missed a call from his wife. Koehler’s phone was then off the grid for a period of two and a half hours.

At 9:37 p.m., security footage from a house along Perfumo Canyon captured a vehicle driving to the See Canyon side. Detectives could not identify the make and model of the car, though.

Koehler’s wife tried calling her husband at 10:32 p.m. Koehler then twice tried to call her. Text messages showed it was the couple’s anniversary.

On Feb. 22, San Luis Obispo police made their first contact with the defendant. Koehler appeared excessively nervous during the encounter, and he never asked who the missing person was or what he had to do with her disappearance, Detective Caleb Kemp testified.

Koehler told police that he texted Marti and later met up with her. Koehler said he dropped Marti off near Madonna Plaza, but police determined that was not true.

Kemp also testified that Koehler changed his phone number five or six days following Jan. 9, even though he had just printed new business cards with the old number.

Bill Posey, a forensic toxicologist, testified Marti had cocaine, morphine and methamphetamine in her system. Posey said there was also alcohol and an anti-worming drug in her system. The drug is prescribed by veterinarians, but it is also used to cut cocaine.

During cross-examination, Koehler’s attorney asked detective Kemp if he thought it was possible Marti suffered a fatal overdose on the night of Jan. 9, and Reed and other friends tried to hide her body in the creek.

Koehler’s attorney also questioned whether it was odd that Reed and the other man who would drive Marti to meet her dates was not with her that night. Kemp said it was not strange because other witnesses said both men were very intoxicated.

Testimony in the preliminary hearing will continue on Thursday. A judge will then rule whether there is enough evidence to proceed to trial.

Koehler is being held in SLO County Jail without bail.


heartbreaking on so many levels


This is a tragic end to a troubled life