In 2369, he was invited by Dr. Beverly Crusher to view a test of Dr. Reyga's metaphasic shielding aboard the starship USS Enterprise-D. Knowing the research had promise, he saw this as an opportunity to steal the technology. He was the most enthusiastic of the small number of scientists present, and awed by being able to observe the solar plasma reactions. Jo'Bril volunteered to pilot the shuttlecraft Justman on a test of the shielding and, at the same time, sabotaged the Enterprise-D sensors in order to make it appear as if the shielding failed and Jo'Bril himself had died. Takaran physiology was extremely resilient, and he put himself into a kind of hibernation state that resembled death, fooling Crusher for the moment.
After he revived himself, Jo'Bril murdered Reyga and made it appear as if he had committed suicide, to further discredit his work. He planned to sneak away with the designs, but, when Crusher found it unlikely that the shield problems could have killed Jo'Bril, she dug further into the incident and discovered the plot. Jo'Bril realized she would take the Justman out again to prove it. He heard this while faking death and stowed away aboard the shuttle. Not knowing he was aboard, she went into the corona. He then cut communications and made it look like the shuttle experienced a warp core breach, planning to take the entire shuttle back to Takara for development into a weapon, however, he was foiled when she overpowered him in a brief struggle for control of the shuttle. Jo'Bril was killed via vaporization when Beverly shot him with a phaser set to maximum. (TNG: "Suspicions")