my father is working in abroad vs my father is working abroad

Some examples from the web:

• My father is working with the FBI, trying to have us killed.
• Silence! My father is working away from home, and my mother is also busy, so I was pretty much alone at home.
• My father is the senior military officer.
• My father is most particular about meal times.
• O'Hara is working in poison ingestion.
• My father is clean, Chuck.
• My father is drunk, he will kill you.
• My awkwardness with my father is well-established.
• You have no idea who my father is.
• General, my father is unaware of my CIA career.
• My father is one of them.
• My father is the Secretary of Defense.
• My father is not an issue.
• My father is still going to impose the tax.
• If my father is in prison, then Philip will be killed.
• My father is gone, presumed dead, and as for me...
• My father is Anthony DiNozzo Sr.
• The real reason you killed my father is because you feared him.
• My father is a cellist, I play the violin.
• My father is again sick, then I thought about going there and...

Some examples from the web:

• My father is working with the FBI, trying to have us killed.
• Silence! My father is working away from home, and my mother is also busy, so I was pretty much alone at home.
• My father is the senior military officer.
• My father is most particular about meal times.
• Over this period, Latvia has lost one fifth of its population; one fifth has emigrated and is working abroad.
• My father is clean, Chuck.
• My father is drunk, he will kill you.
• My awkwardness with my father is well-established.
• You have no idea who my father is.
• General, my father is unaware of my CIA career.
• My father is one of them.
• My father is the Secretary of Defense.
• My father is not an issue.
• My father is still going to impose the tax.
• If my father is in prison, then Philip will be killed.
• My father is gone, presumed dead, and as for me...
• My father is Anthony DiNozzo Sr.
• The real reason you killed my father is because you feared him.
• My father is a cellist, I play the violin.
• My father is again sick, then I thought about going there and...