A spokeswoman in the FBI's Boston field office said she could not confirm or deny any ongoing investigations. Similarly, a spokesman for the Massachusett's Attorney General's office said he could not comment on whether or not the office was investigating, but confirmed they had received Brennan's complaint.
Brennan said she also contacted Yahoo, which shut down the e-mail addresses used in the Craigslist ad by the scammer, the adoption "lawyer" and the supposed orphanage in Cameroon.
When asked for comment about the advertisement, Craigslist responded with a statement from CEO Jim Buckmaster saying, "As always we caution Craigslist users to deal locally with folks you can meet in person. Following this one simple rule avoids virtually all online scam attempts."
Brennan is still in contact with the scammer's alleged lawyer identified in e-mails as Tamajung, and when she questioned him whether this was a scam because his e-mail had changed, Brennan said Tamajung assured her that it was a problem with Yahoo's server that had since been resolved.
Her hometown Abington Police Department assured Brennan they'd do what they could, but that they may never know who was behind it.
"They said often it's difficult to get to the bottom of scams like this," she said.
Ernie Allen, president and CEO of the National Center for Missing and Exploited Children, told ABCNews.com that they are seeing a lot of "scam-type activities."
Brennan's story, he said, is "not something to my knowledge we've seen before, but it's certainly not a surprise."
"It's an outrageous story," he said. "Just takes your heart out for this mom."
He noted that Craigslist, which has come under fire for not taking down advertisements that are not only illegal, but violate company policy, is working with the center and a number of attorneys general to clean up portions of its Web site.
But Craigslist, he said, is not the only Web site where scams can be found.
"I think we've made some headway ... but there are millions of people who are using it responsibly and some that are not," Allen said.
Allen said that while child protection experts understand why families want to set up Web sites to share photos and stories of their children, they have cautioned parents about doing so in a public domain.
"The reality is that when you post pictures, when you pose images, there are risks," he said.
For their part, the Brennans have changed their blog to be password protected and they only allow access for e-mail addresses they know belong to family and friends.
She urged other parents who maintain blogs to do the same as well as finding some way to protect the photos, either through a watermark or low-resolution posting to make them undesirable to others.
"We never though of all the million of photos on the Internet our son would be chosen," she said.
And while they at first were worried for their son's safety, nervous that the scammer was local and trying to take Jake from them, Brennan said they now recognize this is simply about money.
Allen agreed saying that there is very little physical risk to children whose images are used in this way.
"My instinct is that this is pure scam. This is an attempt to use this to steal money from people," he said. "People are trying to sell just about anything they can sell."