Exhibit (a)(4)





September 19, 2006

TO:                  UNIT HOLDERS OF SECURED INCOME L.P.

SUBJECT:             EXTENDED OFFER TO PURCHASE UNITS

Dear Unit Holder:

We are amending the Offer to Purchase and related Letters of Transmittal sent to
you on August 16, 2006, (the "Offer"), which was made by the Purchasers
identified in the Offer. The Purchasers are offering to purchase ANY AND ALL
Units of limited partnership interest (the "Units") in SECURED INCOME L.P., a
Delaware limited partnership (the "Partnership"), not already owned by them for:

              $7.00 per Unit (after the recent $42.10 distribution)
              -----------------------------------------------------

You may wish to consider the following reasons for selling your Units in the
Partnership:

o    UNCERTAINTY OF PARTNERSHIP TERMINATION. The general partner is in
     negotiations to sell the Partnership's remaining property, but it already
     fell out of contract once at a higher price. Thus, there can be no
     assurance that the sale will occur in the near future or at all.

o    REDUCTION OF PHANTOM INCOME FOR 2006. You will not receive sufficient
     distributions to offset the taxable income you must report on your tax
     return. The Partnership has stated that each Unit will be allocated $58 in
     income from the sale of the Westmont property, but the Partnership only
     paid approximately $38 to $42.10 per Unit, depending upon withholding
     taxes. The difference of up to $20 per Unit is phantom income. If you sell
     to us, you will be able to offset this allocation of income with your basis
     in the Units, which was $20 per Unit for original investors when they
     purchased Units. Your basis would change based upon your individual
     circumstances, so you should check with your tax adviser.

o    NO FURTHER WITHHOLDING TAXES FOR NON-RESIDENTS. If you sell your Units to
     us, you will receive the entire $7 per Unit, less any distribution (and
     none is expected). Limited partners who were not residents of New York had
     approximately $4 per Unit of the recent distribution withheld for New York
     state taxes. If and when the Fieldpoint property sells, the Partnership
     will be required to withhold taxes from non-residents of Maryland, reducing
     the net amount of any potential distribution.

o    NO FUTURE IRS FILING REQUIREMENTS / ELIMINATION OF RETIREMENT ACCOUNT FEES.
     If you sell your Units to us this year, the 2006 tax year will be the final
     year for which you will be obligated to file a K-1 for the Partnership with
     your tax return and for which you incur fees for having this investment in
     your IRA or retirement account. This may represent a reduction in costs
     associated with filing complicated tax returns and fees charged by some
     custodians for holding this type of asset. Your decision to sell may have
     other favorable or unfavorable tax consequences and potential sellers
     should consult their individual tax advisers.

The Purchasers are amending the Offer by extending the Expiration Date to
October 6, 2006. You can view the Offer materials as amended on our website at
www.mpfi.com (Click on MPF Tenders) or by calling us at the number below. After
carefully reading the Offer as amended, if you elect to tender your Units, mail
(using the enclosed pre-addressed, postage paid envelope) or fax (then mail) a
duly completed and executed copy of the Letter of Transmittal (printed on pink
paper) and change of address forms, and any other documents required by the
Letter of Transmittal, to the Depositary for the Offer at the address on this
letterhead or via facsimile at (925) 631-9119.

If you have any questions or need assistance, please call the Depository at
800-854-8357.