With no explanation, label each line with "location-GPE", "O", "person-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
Probably
the
instigators
of
his
death
were
his
half-brothers
,
although
the
main
conspirator
was
thought
to
be
Otto
,
who
remained
free
in
Germany
.
Probably:O
the:O
instigators:O
of:O
his:O
death:O
were:O
his:O
half-brothers:O
,:O
although:O
the:O
main:O
conspirator:O
was:O
thought:O
to:O
be:O
Otto:person-other
,:O
who:O
remained:O
free:O
in:O
Germany:location-GPE
.:O