It sounds very much like some kind of clerical or court "shorthand" which may mean something to that particular court but has no universal meaning outside that court system. It can be assumed that the "FEL" probably means "felony" but what the "S" might stand for is anybody's guess.
Adler Fels was created in 1980.
Joseph Fels was born in 1853.
Joseph Fels died in 1914.
Willi Fels was born in 1858.
Willi Fels died in 1946.
Der Fels ended in 1927.
Joseph Fels Barnes died in 1970.
Edmond de Fels was born in 1858.
Edmond de Fels died in 1951.
Samuel Simeon Fels was born in 1860.
Fels Institute of Government was created in 1937.
Joseph Fels Barnes was born in 1907.