I saw a cat is sneaking into the house. vs I saw a cat sneaked into the house

Some examples from the web:

• I saw a baby drowned like a cat.
• I saw a cat drinking the spilled contents.
• I saw a cat that smokes.
• I saw a cat running after the dog.
• I thought I saw a cat stuck in a tree.
• I saw a cat in your tree, so I thought I'd get it down.
• Our 14-year-old is sneaking into high school parties.
• I saw a cat wearing the same sweater as its person.
• The nature of a cat is its unpredictability.
• She has a cat. The cat is white.
• I saw a wedding today at Lin Village.
• There's so much hair in there, I saw a cat using a lint roller.
• A cat is not always a cat.
• I saw the sighs for months before I saw a Doctor.
• A cat is locked in a steel chamber with a bottle of cyanide.
• The only thing I want to give a cat is its name and address to my dogs.
• A cat is, above all, a furry animal.
• A cat is not a person!
• When a cat is given the vaccine, the immune system recognises the bacteria as' foreign' and makes a special type of antibodies against them.
• When a cat is given the vaccine, the immune system recognises the FeLV proteins as' foreign' and makes antibodies against them.

Some examples from the web:

• I saw a baby drowned like a cat.
• I saw a cat drinking the spilled contents.
• I saw a cat that smokes.
• I saw a cat running after the dog.
• I thought I saw a cat stuck in a tree.
• I saw a cat in your tree, so I thought I'd get it down.
• I saw a man running out of the house.
• I saw a black cat run into the house.
• One day Cetin sneaked into the janitor's apartment and put a cat in his fridge.
• I saw a cat wearing the same sweater as its person.
• Today I saw a box like this one in the house where they killed a boy.
• I saw a wedding today at Lin Village.
• There's so much hair in there, I saw a cat using a lint roller.
• I saw the sighs for months before I saw a Doctor.
• I just saw a cat with a hammer jumping out the window.
• Saw a cat smile like that once.
• I saw you turn into Joey right before my eyes. I saw a killer...
• It's like having a cat around the house.
• A cat crawled across the house.
• A cat crawled across the house.