During Hernandez's arraignment last week, prosecutors said Jenkins had been speaking with investigators until she received a phone call from Hernandez telling her to keep quiet. But if the case goes to trial, she may not have the option of refusing to address what she does or does not know.
Since the couple is not legally married, Jenkins does not have the option of using the spousal privilege law in Massachusetts, which would allow her to object to a request by prosecutors to give testimony in Hernandez's trial.
In an interview with CBS News' Crimesider, Patrick J. Murphy, a Massachusetts domestic violence defense attorney and an expert on the state's spousal privilege law, said the fact that Jenkins and Hernandez are engaged and have a child together does not allow her to refuse to take the stand.
Murphy says, in order to use the privilege, you must be married to the party that is subject to a criminal prosecution. He says there is no common-law privilege in Massachusetts that is applicable to unmarried individuals living together, as in the case of Hernandez and Jenkins.
On Tuesday, Bristol County Sheriff Thomas M. Hodgson told USA Today that he will do everything he can to keep Hernandez from marrying Jenkins while behind bars at the Bristol County jail. While there have been no reports that Hernandez is planning to do so, Hodgson says he won't allow it.
"I don't subscribe to that. I feel that those rights are things that you access on the outside, if you're a good citizen," he told the paper. "We'll do everything we can to not have that happen."
Murphy says it doesn't seem right to prevent someone from marriage.
"It could be interpreted as the Sheriff acting as part of the prosecution," Murphy told Crimesider. "If I was [Hernandez's] lawyer, I would speak to the Department of Corrections about that."
He continued, "Anyone can get married, as long as they meet the basic qualifications."
Murphy says it would likely be difficult to bar a justice of the peace from entering the jail and performing the ceremony. For example, Murphy says, one of Hernandez's lawyers could easily opt to be a justice of the peace and perform the ceremony during a routine jail visit.
If the couple does choose to legally marry and is able to do so while Hernandez is behind bars, Murphy says that could have the potential to influence the ex-NFL star's trial in a significant way. He says Jenkins would then be allowed to use the spousal privilege and opt out of testifying. According to Murphy, the privilege is valid in Massachusetts even if the couple was not married at the time of the incident in question.
He says it seems plausible Jenkins would know information regarding the case.
"They lived in the same house together. You would imagine she would overhear or see something," Murphy told Crimsider.Hernandez, 23, is being held without bail after pleading not guilty to first-degree murder in the death of semi-pro football player Odin Lloyd, 27, of Dorchester. His body was found June 17 less than a mile from Hernandez's home in North Attleborough, Mass.
A judge says that while the case against Hernandez is circumstantial at this point, it is "very, very, strong."
Defense attorneys for Hernandez say it could be over a year before the case goes to trial.