On 8 May JG 1 flew a successful intercept with JG 3 against the 2nd Bomb Divisions B-17s raid on Berlin. JG 1 caught the division without escort and downed 13. The US bomber force lost 36 on the day, with 13 fighters, but 32 RLV fighters were destroyed. On 11 May, JG 1 lost its leader Walter Oesau, killed in combat with P-38s—purportedly ill, he flew an intercept mission after being called a coward by "Reichsmarschall" Göring. Oesau's death in combat with the US 474th Fighter Group, operational for two weeks, led to Bär becoming interim commander and Herbert Ihlefeld becoming the permanent wing commander for the duration of the war. It is said that an order by Galland to Oesau to cease flying arrived the day he was killed. Only twenty-four hours later, the Eighth targeted the Leuna works. JG 1 reached the bomber stream but were attacked by the US 78th Fighter Group. III. "Gruppe" fought a defensive action against the escorts, while the Fw 190 "gruppen" sought out unescorted bombers. I. "Gruppe" failed to attack and returned to Rotenburg to prepare for a second sortie. II. "Gruppe" attacked the 2nd Bomb Division in a head-on attack, and they claimed five bombers—these were the only Luftwaffe formations to be sighted by the American division. On 28 May, JG 1 defended against the Eighth as it targeted the Junkers factory at Dessau and oil refineries at Leuna, Ruhland, Magdeburg and Zeitz. JG 1 led an assault on the 13th Combat Wing, 3d Bombardment Division. Approximately 180 Fw 190s and Bf 109s were involved—37 were shot down by P-51s killing 13 pilots and wounded another 13. The 4th and 354th Fighter Group claimed 33 German fighters.