Uber has denied stealing self-driving technology from Google, as it attempts to convince a US judge not to grant an injunction barring the use of the tech in its vehicles.

Waymo, a company spun out of Google, brought a lawsuit in February, accusing ex-Waymo employee Andrew Levandowski of stealing 14,000 documents relating to LiDAR, technology which is used to guide autonomous vehicles. Levandowski subsequently went on to co-found self-driving truck company Otto, which Uber acquired last year for $660m.

Uber’s defence hinges on two key points. Firstly, it says, it has been unable to locate any of the 14,000 files on its servers. Waymo has dismissed this argument, pointing to the fact that its search has so far not included Levandowski’s own PC. This is because, in a recent court hearing, he invoked the Fifth Amndment, which allows US citizens to refuse to disclose any information which could put them at risk of self-incrimination.

US District Judge William Alsup has said, however, that he will not accept Uber’s defence of being unable to find the files as a reason not to grant the injunction. Speaking at a hearing on Wednesday, he said:

“If all you can show is that you cant find them in your files, theres going to be a preliminary injunction of some sort. It cant be helped. You have got to do more than what you are telling me.”

Uber’s second line of defence is that the LiDAR technology it is developing is completely different to the tech detailed in the documents allegedly stolen by Levandowski. In a statement, Ubers associate general counsel Angela Padilla said:

“Waymos injunction motion is a misfire: There is no evidence that any of the 14,000 files in question ever touched Ubers servers, and Waymos assertion that our multi-lens LiDAR is the same as their single-lens LiDAR is clearly false. If Waymo genuinely thought that Uber was using its secrets, it would not have waited more than five months to seek an injunction. Waymo doesnt meet the high bar for an injunction, which would stifle our independent innovation — probably Waymos goal in the first place.”

The case doesn’t look great for Uber, however. Among his other comments at Wednesday’s hearing, Judge Alsup said: “This is an extraordinary case. I have never seen a record this strong in 42 years. So you are up against it.”