(Alternative answers have been given in a few cases, but there are usually several possible corrections.)
(1) After a few day, people noticed a peacock had been kill again.
After a few days, people noticed a peacock had been killed again.
(2) The next day five more peacock kill, so people worried.
The next day five more peacocks were killed, so people were worried.
(3) Later the murder of birds repeated again.
Later, the murder of birds was repeated. (OR: Later, more birds were murdered.)
(4) A woman named Brenda. She was charged murder.
A woman named Brenda was charged with murder.
(5) One lady stabbed another lady and baby born died.
One lady (OR: "woman") stabbed another woman and her baby was born dead.
(6) Another case was happened in Vancouver in 1991.
Another case was happened in Vancouver in 1991.
(7) On May 28, Brenda was born a child in her bathroom.
On May 28, Brenda had a baby in her bathroom. (OR: On May 28, Brenda gave birth in her bathroom.)
(8) He couldn't find a job, he had a mental illness.
He couldn't find a job. He had a mental illness. (OR: He couldn't find a job because he had a mental illness.)