"Our orders are to bring back information on the Minbari and that's just what I'm going to do!"
- – Captain Jankowski, shortly before opening fire on the Valen'Tha
In his time as a starship captain, Jankowski had developed a reputation among those who served under him as a loose cannon and was known to be bad at handling first contact situations. Even though a tribunal cleared him of all responsibility, some still believed he was at least partly to blame for the "Omega Incident". Such was the concern of some officers over his competence that Commander John Sheridan turned down the offer to serve as Jankowski's first officer.
Contact with the Minbari
In July 2245, the Prometheus led an expedition from the Jericho 3 station into Minbari space. Jankowski was under orders to survey the disposition of their forces but to avoid any first contact situations, unless authorized to do so. A few weeks previous, Jankowski had lost his first officer to the EAS Churchill and through General Robert Leftcourt offered the position to John Sheridan. Sheridan turned down his offer in favor of remaining aboard the Lexington, so the position went instead to Commander Alan Chafin.
Shortly after arriving at one of the fleet's rendezvous points, the Prometheus's sensors detected a silhouette at the edge of their range. Jankowski knew they were well away from the Minbari transfer points and immediately grew suspicious, speculating that the Minbari could be out looking for them. Deciding not to strain the engines with a second jump into hyperspace so soon after jumping in and seeing an opportunity to gain some intelligence and a commendation, he gave the order to follow the Minbari ship and turn the scanner up to maximum, believing the Minbari would not be able to detect them. The Prometheus's scanners were unable to lock on because of the Minbari ships' stealth technology, and could only provide silhouettes of the main cruiser and its support ships. Ignoring Commander Chafin's concerns about initiating contact, Jankowski ordered the fleet to move in closer. At this point, the Minbari cruiser changed course to intercept and began a scan of the Earth fleet. Jankowski order the fleet to jump but found the powerful Minbari scanners were jamming the ship's electrical systems, preventing them from jumping out. Captain Jankowski ordered the ship to red alert and attempted to open a channel to the Minbari, but the message was not acknowledged. With the Minbari ships opening its gun ports and the Prometheus's own sensors still jammed, Chafin could not determine if the weapons were locked onto them. Just then, the sensors picked up an energy surge, and in fear of an immediate attack, Jankowski panicked and order all forward batteries to open fire. The Minbari ships were caught by surprise and were severely damaged. As soon as the Minbari scanner arrays were hit, the Prometheus's jump engines came back online and Jankowski ordered the fleet to jump to hyperspace.
Upon returning to Earth space, Jankowski made a full report on his encounter with the hostile alien fleet and was lauded a hero for defeating an enemy even the Centauri were afraid of. Back at Earth Dome, Captain Jankowski attended a celebration of his "victory" with various other Earthforce officers, diplomats, and officials, while video footage of the incident was played for the crowd over and over. An aide to the Earth Alliance president congratulated Jankowski and remarked to General Leftcourt that he had made the right choice in selecting Jankowski for the mission. Just then, Jankowski approached Captain Roger Sterns and Commander Sheridan and proceeded to gloat over his success and ridiculed Sheridan's decision to remain where he was. Neither Sheridan nor Sterns were as impressed by what they saw on the screens as others, saying Jankowski looked more like a trapped deer. Jankowski maintained that he had sent a message to all aliens that Earth should not be taken for granted. At that point, Centauri Ambassador Londo Mollari chimed in, saying he was indeed correct that a message had been sent, and than that wasn't a party, but a wake. His words were confirmed right after, when the party was cut short by a special ISN bulletin showed live footage from the Jericho 3 station, under attack from the Minbari fleet. The Earth-Minbari War had begun.
Over the next few weeks, Jankowski was brought before a court martial, stripped of rank, and offered to the Minbari as a means of making amends. When the offer was rebuffed, he was confined to quarters.
Not long after, a deal was struck between the Narn Regime and the Earth Alliance. General Lefcourt sent for Jankowski to come to his office for further debriefing; as he was the only captain to have survived in battle against the Minbari, some wanted to offer him some advisory post. When he failed to respond, a military attaché was sent to fetch him. What he found in Jankowski's quarters were the remains of the former captain seated before a video monitor playing looped footage of the destruction of Earth ships and colonies, intercut with a bridge recording of his first contact with the Minbari. Next to the body was found a used PPG and a note that read simply, "On my head."