At the time of his death he was married but had no children and lived on Laxenburger Street in Favoriten, the 10th district of Vienna.

In 1930, Planetta joined the Nazi Party (member number 300,772)[1] and, together with Fridolin Glass and Franz Holzweber, founded the "German Soldiers' Association for the Registration of National Socialists in the Austrian Armed Forces".

In 1933, after being discharged from the Bundesheer for being a Nazi sympathizer, Planetta played a leading role in the formation of SS Standarte 89 (later SS-Standarte 89 "Holzweber"), which was created under the direct orders of Adolf Hitler to be a group of shock troops designed to create chaos on the streets of Austria.

[2] On 30 July, a military tribunal tried Planetta and his accomplice, Franz Holzweber, for murder and high treason.

While Dollfuß was less than five ft 0 in (1.52 m) tall, Planetta claimed to have seen a big man in the room, whom he ordered to put his hands in the air.

"[3] In response to Planetta's telling of what happened, the presiding judge, Albert Oberweger, replied "Your story is too stupid to be believed.

They were hanged only three hours after their convictions, the minimum wait time required before carrying out a death sentence in Austria.

When Holzweber's widow attempted to place a ribbon of German colors on the coffin, officials told her that if she did, she'd be charged with high treason.

Less than a week after the executions of Planetta and Holzweber, their lawyer, Eric Fuehrer, was arrested for being a Nazi sympathizer.