Additionally, police found it incredibly suspicious that the ransom note was two pages long and was written on a legal pad from inside the house.
Apparently, it is highly uncommon for kidnappers or thieves to write the note at the scene of the crime.
Also, the amount the kidnappers asked for was highly specific—and was the exact amount John Ramsey had received as his bonus that year.
As the investigation continued, police discovered that Patsy Ramsey's handwriting was almost a perfect match to the ransom note, but they couldn't conclusively prove that she did write it.

In general, the case was ripe with investigative errors, and it's one reason why the case became so diluted so quickly.
For one, the police became hell-bent on proving that the Ramseys did kill their daughter, and didn't pursue any other viable leads.
Also, they allowed a lot of people to enter the house before and after the body was discovered, which compromised a lot of the evidence.
In 2002, the case was sent to the district attorney because the Ramsey family didn't think the police were doing a good job.