Seller's disclosure - when the seller does not disclose some info

[Mariama R.]

Should it send off alarm bells to a potential investor not to buy a property if the seller claims that he/she does not know the age of the roof, does not know if the roof has ever been replaced, does not disclose the nature of a minor repair to the roof, or what the original material that was used for the water pipes, although some of the pipes were replaced with copper, and if the seller claims that he/she is not sure of the age of the gas water heater, but claims that it was replaced 8 years ago with a major rehab? The owner has owned the property for 10 years and presumably rented for this long since he/she never lived in it.  There are also 2 seller disclosures - a 2014 one where there was even more undisclosed data and the seller checked a box for, but did not disclose that there could be a condition, including but not limited to financial one, that may prevent the seller from completing the sale of the property.  In the second seller disclosure which is more current and dated 2015, this box is checked "no".  Should I be concerned and should this be a red flag causing me to back away from the purchase, or can much of these issues or issues with the property be determined in an inspection? Also, how can I analyze what the Cap Exp will be if  the seller does not disclose certain items, such as the age of the roof, whether or not the roof has been replaced and the nature of the repairs of the roof and other items?  Do I simply press the seller for this information or if he refuses to give it, use this as a negotiating point to make a lower priced offer? Thanks,